split mpc8xx hooks from cmd_ide.c

move most of mpc8xx hooks from cmd_ide.c into ide_preinit() and newly created
ide_init_postreset() (invoked after calling ide_reset after ide_preinit),
some cleanup to make checkpatch happy, enable IDE init hooks in configs of
affected boards.
confusingly, these hooks are used by more than just mpc8xx-based boards, and
therefore are placed in arch/ppc/lib/

note: checkpatch still emits warnings about using volatile

Signed-off-by: Pavel Herrmann <morpheus.ibis@gmail.com>
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index 965f9ea..808021c 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -50,6 +50,7 @@
 COBJS-y	+= extable.o
 COBJS-y	+= interrupts.o
 COBJS-$(CONFIG_CMD_KGDB) += kgdb.o
+COBJS-${CONFIG_CMD_IDE} += ide.o
 COBJS-y	+= time.o
 
 # Workaround for local bus unaligned access problems