ramips: switch to kernel 5.10

Tested on mt7621 (Redmi AC2100) and running stable for several months.

Signed-off-by: Rui Salvaterra <rsalvaterra@gmail.com>
Tested-by: Stijn Segers <foss@volatilesystems.org>
Tested-by: Eneas U de Queiroz <cotequeiroz@gmail.com>

target/linux/ramips/Makefile

@@ -10,8 +10,7 @@ BOARDNAME:=MediaTek Ralink MIPS
 SUBTARGETS:=mt7620 mt7621 mt76x8 rt288x rt305x rt3883
 FEATURES:=squashfs gpio
 
-KERNEL_PATCHVER:=5.4
-KERNEL_TESTING_PATCHVER:=5.10
+KERNEL_PATCHVER:=5.10
 
 define Target/Description
 	Build firmware images for Ralink RT288x/RT3xxx based boards.