powerpc/boot: Change spaces to tabs

For C code spaces versus tabs is just a religious issue,
but for Makefiles it actually matters.

This patch fixes he following errors:
/home/bunk/linux/kernel-2.6/git/linux-2.6/arch/powerpc/boot/Makefile:166: *** missing separator.  Stop.
/home/bunk/linux/kernel-2.6/git/linux-2.6/arch/powerpc/boot/Makefile:171: *** missing separator.  Stop.

Since this was inside an ifdef DTC_GENPARSER it was not a problem unless
someone wanted to regenerate the shipped generated files.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>