kernel: bump 5.4 to 5.4.124

Manually rebased
  generic/hack-5.4/662-remove_pfifo_fast.patch
  ramips/patches-5.4/0048-asoc-add-mt7620-support.patch

All others updated automatically.

Compile-tested on: armvirt/64, x86/generic, ath79/generic, ramips/mt7621
Runtime-tested on: armvirt/64, x86/generic, ath79/generic

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

target/linux/ramips/patches-5.4/0048-asoc-add-mt7620-support.patch

@@ -18,24 +18,6 @@ Signed-off-by: John Crispin <blogic@openwrt.org>
  create mode 100644 sound/soc/ralink/mt7620-i2s.c
  create mode 100644 sound/soc/ralink/mt7620-wm8960.c
 
---- a/arch/mips/ralink/of.c
-+++ b/arch/mips/ralink/of.c
-@@ -13,6 +13,7 @@
- #include <linux/of_fdt.h>
- #include <linux/kernel.h>
- #include <linux/memblock.h>
-+#include <linux/module.h>
- #include <linux/of_platform.h>
- #include <linux/of_address.h>
- 
-@@ -24,6 +25,7 @@
- #include "common.h"
- 
- __iomem void *rt_sysc_membase;
-+EXPORT_SYMBOL(rt_sysc_membase);
- __iomem void *rt_memc_membase;
- 
- __iomem void *plat_of_remap_node(const char *node)
 --- a/sound/soc/Kconfig
 +++ b/sound/soc/Kconfig
 @@ -60,6 +60,7 @@ source "sound/soc/mxs/Kconfig"