[PATCH] Remove bzImage target

Since the documentation no longer tells people to 'make bzImage', and
with the previous patch nothing more than 'make' is required to get the
right bootable images (just like on i386 now), this removes the bzImage
-> zImage target redirect on ARCH=powerpc

Signed-off-by: Tom Rini <trini@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>