lmb: Switch to generic arch_lmb_reserve_generic()

Switch arc/arm/m68k/microblaze/mips/ppc arch_lmb_reserve() to
arch_lmb_reserve_generic().

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Alexey Brodkin <alexey.brodkin@synopsys.com>
Cc: Angelo Dureghello <angelo@sysam.it>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Cc: Hai Pham <hai.pham.ud@renesas.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Cc: Tom Rini <trini@konsulko.com>
Cc: Wolfgang Denk <wd@denx.de>
diff --git a/arch/m68k/lib/bootm.c b/arch/m68k/lib/bootm.c
index 51a6f93..27729db 100644
--- a/arch/m68k/lib/bootm.c
+++ b/arch/m68k/lib/bootm.c
@@ -32,23 +32,7 @@
 
 void arch_lmb_reserve(struct lmb *lmb)
 {
-	ulong sp;
-
-	/*
-	 * Booting a (Linux) kernel image
-	 *
-	 * Allocate space for command line and board info - the
-	 * address should be as high as possible within the reach of
-	 * the kernel (see CONFIG_SYS_BOOTMAPSZ settings), but in unused
-	 * memory, which means far enough below the current stack
-	 * pointer.
-	 */
-	sp = get_sp();
-	debug ("## Current stack ends at 0x%08lx ", sp);
-
-	/* adjust sp by 1K to be safe */
-	sp -= 1024;
-	lmb_reserve(lmb, sp, (CONFIG_SYS_SDRAM_BASE + gd->ram_size - sp));
+	arch_lmb_reserve_generic(lmb, get_sp(), gd->ram_top, 1024);
 }
 
 int do_bootm_linux(int flag, int argc, char *const argv[],