[openwrt/openwrt] gemini: Bump kernel to v5.15

[LEDE Commits]

ynezz pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/81da8a295bad2d7ea29bb19493a75b42e5d9ad63

commit 81da8a295bad2d7ea29bb19493a75b42e5d9ad63
Author: Linus Walleij <linus.walleij at linaro.org>
AuthorDate: Mon Apr 11 23:46:19 2022 +0200

    gemini: Bump kernel to v5.15
    
    It's working well on all tested targets, so let's move
    Gemini forward to v5.15. imx is already bumped so why not.
    
    Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
 target/linux/gemini/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/linux/gemini/Makefile b/target/linux/gemini/Makefile
index 95a5a87eaa..d5c9bbad13 100644
--- a/target/linux/gemini/Makefile
+++ b/target/linux/gemini/Makefile
@@ -10,7 +10,7 @@ BOARDNAME:=Cortina Systems CS351x
 FEATURES:=squashfs pci rtc usb dt gpio display ext4 rootfs-part boot-part
 CPU_TYPE:=fa526
 
-KERNEL_PATCHVER:=5.10
+KERNEL_PATCHVER:=5.15
 
 define Target/Description
 	Build firmware images for the StorLink/Cortina Gemini CS351x ARM FA526 CPU