kernel: bump 5.15 to 5.15.88
No patches affected by kernel bump/checksum automatically updated
Build system: x86_64
Build-tested: bcm2711/RPi4B, filogic/xiaomi_redmi-router-ax6000-ubootmod
Run-tested: bcm2711/RPi4B, filogic/xiaomi_redmi-router-ax6000-ubootmod
Signed-off-by: John Audia <[email protected]>