bcm27xx: switch to kernel 5.10

After testing it on RPi B+ and RPi 4B it seems stable enough to enable it on
OpenWrt master.

Signed-off-by: Álvaro Fernández Rojas <[email protected]>

target/linux/bcm27xx/Makefile

@@ -11,7 +11,7 @@ BOARDNAME:=Broadcom BCM27xx
 FEATURES:=ext4 audio usb usbgadget display gpio fpu squashfs rootfs-part boot-part
 SUBTARGETS:=bcm2708 bcm2709 bcm2710 bcm2711
 
-KERNEL_PATCHVER=5.4
+KERNEL_PATCHVER=5.10
 
 define Target/Description
 	Build firmware image for Broadcom BCM27xx SoC devices.