lantiq: fix compilation warning in cfi_mtdset_0001

Some write buffer functions are not used when FORCE_WORD_WRITE is set to 1.
So the compile warning messages are output if FORCE_WORD_WRITE is 1. To
resolve this disable the write buffer functions if FORCE_WORD_WRITE is 1.

This fix compilation warning:
drivers/mtd/chips/cfi_cmdset_0001.c:307:13: warning: 'fixup_use_write_buffers' defined but not used [-Wunused-function]
  307 | static void fixup_use_write_buffers(struct mtd_info *mtd)
      |             ^~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>

target/linux/lantiq/patches-5.15/0302-mtd-cfi_cmdset_0001-Disable-write-buffer-functions-i.patch

@@ -0,0 +1,62 @@
+From 118fe2c88b35482711adeee0d8758bddfe958701 Mon Sep 17 00:00:00 2001
+From: Aleksander Jan Bajkowski <olek2@wp.pl>
+Date: Sat, 6 May 2023 14:32:00 +0200
+Subject: [PATCH] mtd: cfi_cmdset_0001: Disable write buffer functions if
+ FORCE_WORD_WRITE is 1
+
+Some write buffer functions are not used when FORCE_WORD_WRITE is set to 1.
+So the compile warning messages are output if FORCE_WORD_WRITE is 1. To
+resolve this disable the write buffer functions if FORCE_WORD_WRITE is 1.
+
+This is similar fix to: 557c759036fc3976a5358cef23e65a263853b93f.
+
+Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
+---
+ drivers/mtd/chips/cfi_cmdset_0001.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+--- a/drivers/mtd/chips/cfi_cmdset_0001.c
++++ b/drivers/mtd/chips/cfi_cmdset_0001.c
+@@ -61,8 +61,10 @@
+ 
+ static int cfi_intelext_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
+ static int cfi_intelext_write_words(struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
++#if !FORCE_WORD_WRITE
+ static int cfi_intelext_write_buffers(struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
+ static int cfi_intelext_writev(struct mtd_info *, const struct kvec *, unsigned long, loff_t, size_t *);
++#endif
+ static int cfi_intelext_erase_varsize(struct mtd_info *, struct erase_info *);
+ static void cfi_intelext_sync (struct mtd_info *);
+ static int cfi_intelext_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len);
+@@ -304,6 +306,7 @@ static void fixup_use_point(struct mtd_i
+ 	}
+ }
+ 
++#if !FORCE_WORD_WRITE
+ static void fixup_use_write_buffers(struct mtd_info *mtd)
+ {
+ 	struct map_info *map = mtd->priv;
+@@ -314,6 +317,7 @@ static void fixup_use_write_buffers(stru
+ 		mtd->_writev = cfi_intelext_writev;
+ 	}
+ }
++#endif /* !FORCE_WORD_WRITE */
+ 
+ /*
+  * Some chips power-up with all sectors locked by default.
+@@ -1703,6 +1707,7 @@ static int cfi_intelext_write_words (str
+ }
+ 
+ 
++#if !FORCE_WORD_WRITE
+ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
+ 				    unsigned long adr, const struct kvec **pvec,
+ 				    unsigned long *pvec_seek, int len)
+@@ -1931,6 +1936,7 @@ static int cfi_intelext_write_buffers (s
+ 
+ 	return cfi_intelext_writev(mtd, &vec, 1, to, retlen);
+ }
++#endif /* !FORCE_WORD_WRITE */
+ 
+ static int __xipram do_erase_oneblock(struct map_info *map, struct flchip *chip,
+ 				      unsigned long adr, int len, void *thunk)