[new uImage] Provide ability to restrict region used for boot images

Allow the user to set 'bootm_low' and 'bootm_size' env vars as a way
to restrict what memory range is used for bootm.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Marian Balakowicz <m8@semihalf.com>
diff --git a/lib_m68k/bootm.c b/lib_m68k/bootm.c
index 8429ca0..eca044e 100644
--- a/lib_m68k/bootm.c
+++ b/lib_m68k/bootm.c
@@ -57,12 +57,14 @@
 	int ret;
 
 	ulong cmd_start, cmd_end;
-	ulong bootmap_base = 0;
+	ulong bootmap_base;
 	bd_t  *kbd;
 	ulong ep = 0;
 	void  (*kernel) (bd_t *, ulong, ulong, ulong, ulong);
 	struct lmb *lmb = images->lmb;
 
+	bootmap_base = getenv_bootm_low();
+
 	/*
 	 * Booting a (Linux) kernel image
 	 *