[openwrt/openwrt] ramips: Switch default kernel to 5.15

[LEDE Commits]

stintel pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/77d061167cf8a7edb3ea7cbc9926f25c8ac8fe1e

commit 77d061167cf8a7edb3ea7cbc9926f25c8ac8fe1e
Author: Rodrigo B. de Sousa Martins <rodrigo.sousa.577 at gmail.com>
AuthorDate: Tue Nov 15 16:05:16 2022 -0300

    ramips: Switch default kernel to 5.15
    
    I tested kernel 5.15 on my device for several times without any problems.
    In my tests, 5.15 kernel has performance improvements such MGLRU.
    Finally, initial kernel 6.1 support is imminent. All ramips subtargets have
    5.15 as testing kernel. So, it's time to change.
    
    Tested on my Archer C6 v3.2 (mt7621)
    
    Signed-off-by: Rodrigo B. de Sousa Martins <rodrigo.sousa.577 at gmail.com>
    [reformat commit subject and message]
    Signed-off-by: Stijn Tintel <stijn at linux-ipv6.be>
---
 target/linux/ramips/Makefile | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/target/linux/ramips/Makefile b/target/linux/ramips/Makefile
index 7d34dfe676..77b82d5334 100644
--- a/target/linux/ramips/Makefile
+++ b/target/linux/ramips/Makefile
@@ -10,8 +10,7 @@ BOARDNAME:=MediaTek Ralink MIPS
 SUBTARGETS:=mt7620 mt7621 mt76x8 rt288x rt305x rt3883
 FEATURES:=squashfs gpio
 
-KERNEL_PATCHVER:=5.10
-KERNEL_TESTING_PATCHVER:=5.15
+KERNEL_PATCHVER:=5.15
 
 define Target/Description
 	Build firmware images for Ralink RT288x/RT3xxx based boards.