kernel: add linux 5.10 support

Signed-off-by: Felix Fietkau <nbd@nbd.name>

target/linux/generic/pending-5.10/333-arc-enable-unaligned-access-in-kernel-mode.patch

@@ -0,0 +1,24 @@
+From: Alexey Brodkin <abrodkin@synopsys.com>
+Subject: arc: enable unaligned access in kernel mode
+
+This enables misaligned access handling even in kernel mode.
+Some wireless drivers (ath9k-htc and mt7601u) use misaligned accesses
+here and there and to cope with that without fixing stuff in the drivers
+we're just gracefully handling it on ARC.
+
+Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
+---
+ arch/arc/kernel/unaligned.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/arch/arc/kernel/unaligned.c
++++ b/arch/arc/kernel/unaligned.c
+@@ -202,7 +202,7 @@ int misaligned_fixup(unsigned long addre
+ 	char buf[TASK_COMM_LEN];
+ 
+ 	/* handle user mode only and only if enabled by sysadmin */
+-	if (!user_mode(regs) || !unaligned_enabled)
++	if (!unaligned_enabled)
+ 		return 1;
+ 
+ 	if (no_unaligned_warning) {