ppc: lmb: move arch specific lmb reservations to arch_misc_init()

All the current function definitions of arch_lmb_reserve() are doing
the same thing -- reserve the U-Boot memory region. The powerpc(ppc)
architecture, in addition, is making some LMB reservations for the
bootm related image loading. Move these ppc specific reservations to
the arch_misc_init() function. This allows to move the U-Boot memory
region reservation to a different function, and remove
arch_lmb_reserve() in a subsequent commit.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/Kconfig b/lib/Kconfig
index 6a93383..e352b55 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -1102,6 +1102,7 @@
 	bool "Enable the logical memory blocks library (lmb)"
 	default y if ARC || ARM || M68K || MICROBLAZE || MIPS || \
 		     NIOS2 || PPC || RISCV || SANDBOX || SH || X86 || XTENSA
+	select ARCH_MISC_INIT if PPC
 	help
 	  Support the library logical memory blocks. This will require
 	  a malloc() implementation for defining the data structures