powerpc: Pull out MPC106 (grackle) initialization code into its own file

This is so that the 32-bit CHRP code can use it.  The MPC106
initialization code is now in arch/powerpc/sysdev/grackle.c and
is controlled by CONFIG_PPC_MPC106.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
index f3c9e61..97119c0 100644
--- a/arch/powerpc/sysdev/Makefile
+++ b/arch/powerpc/sysdev/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_MPIC)		+= mpic.o
 obj-$(CONFIG_PPC_INDIRECT_PCI)	+= indirect_pci.o
 obj-$(CONFIG_PPC_I8259)		+= i8259.o
+obj-$(CONFIG_PPC_MPC106)	+= grackle.o