powerpc: Remove unused config in the Makefile

The patch below removes an unused config variable found by using a kernel
cleanup script.
Note: I did try to cross compile these but hit erros while doing so..
(gcc is not setup to cross compile) and am unsure if anymore needs to be done.
Please have a look if/when anybody has free time.
Signed-off-by: NJustin P. Mattock <justinmattock@gmail.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/Makefile

@@ -78,7 +78,6 @@ obj-$(CONFIG_PPC_FSL_BOOK3E)	+= cpu_setup_fsl_booke.o dbell.o
 obj-$(CONFIG_PPC_BOOK3E_64)	+= dbell.o
 
 extra-y				:= head_$(CONFIG_WORD_SIZE).o
-extra-$(CONFIG_PPC_BOOK3E_32)	:= head_new_booke.o
 extra-$(CONFIG_40x)		:= head_40x.o
 extra-$(CONFIG_44x)		:= head_44x.o
 extra-$(CONFIG_FSL_BOOKE)	:= head_fsl_booke.o