kbuild: mkcompile_h: trivial cleanups
kbuild: mkcompile_h: trivial cleanups

UTS_TRUNCATTE is simpler this way, and now editors idetify this as a
shell script.

Signed-off-by: Felipe Contreras <de77a8b9cd239b204c19c52ed62e48ab47243362@gmail.com>
Acked-by: WANG Cong <0f114804888b88d50037b04b42e57b858d851b87@gmail.com>
Signed-off-by: Sam Ravnborg <f16bed56189e249fe4ca8ed10a1ecae60e8ceac0@ravnborg.org>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs