Change max size of uncompressed uImage's to 8MByte and add
CFG_BOOTM_LEN to adjust this setting.

As mentioned by Robin Getz on 2005-05-24 the size of uncompressed
uImages was restricted to 4MBytes. This default size is now
increased to 8Mbytes and can be overrided by setting CFG_BOOTM_LEN
in the board config file.

Patch by Stefan Roese, 13 Mar 2006
diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c
index a20e584..aeb7842 100644
--- a/common/cmd_bootm.c
+++ b/common/cmd_bootm.c
@@ -1,5 +1,5 @@
 /*
- * (C) Copyright 2000-2002
+ * (C) Copyright 2000-2006
  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  *
  * See file CREDITS for list of people who contributed to this
@@ -140,6 +140,10 @@
 extern void lynxkdi_boot( image_header_t * );
 #endif
 
+#ifndef CFG_BOOTM_LEN
+#define CFG_BOOTM_LEN	0x800000	/* use 8MByte as default max gunzip size */
+#endif
+
 image_header_t header;
 
 ulong load_addr = CFG_LOAD_ADDR;		/* Default Load Address */
@@ -150,7 +154,7 @@
 	ulong	addr;
 	ulong	data, len, checksum;
 	ulong  *len_ptr;
-	uint	unc_len = 0x400000;
+	uint	unc_len = CFG_BOOTM_LEN;
 	int	i, verify;
 	char	*name, *s;
 	int	(*appl)(int, char *[]);