kbuild: correct initramfs compression comment
kbuild: correct initramfs compression comment

Fix the Makefile comment since bzip2 is now supported.

Signed-off-by: Robert P. J. Day <01aa5cd9a29907856ec6ddeebcb643ede4c45b8b@crashcourse.ca>
Signed-off-by: Sam Ravnborg <f16bed56189e249fe4ca8ed10a1ecae60e8ceac0@ravnborg.org>

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