vendor: build: update kernel.mk

taken from LOS
1fdbf7ad8be3865f07400023ed0ec8ccd16cb869
https://github.com/LineageOS/android_vendor_lineage/commits/lineage-15.1/build/tasks/kernel.mk

Change-Id: Ibf393e8e6ab0189999184fbd8ace2d2c326caaef
1 file changed