CRIS v32: Update boot Kbuild makefile.
CRIS v32: Update boot Kbuild makefile.

- Remove old specific targets, use more generic ones instead.
- Use if_changed to avoid creating new images when no change.

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