nvram: fix regression in finding NVRAM beginning

The loop was giving up too early as it never expected NVRAM smaller
than 0x10000.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

SVN-Revision: 45578

package/utils/nvram/src/nvram.h

@@ -113,6 +113,7 @@ char * nvram_find_staging(void);
 #define	NVRAM_ROUNDUP(x, y)	((((x)+((y)-1))/(y))*(y))
 
 /* NVRAM constants */
+#define NVRAM_MIN_SPACE			0x8000
 #define NVRAM_SPACE			0x10000
 #define NVRAM_MAGIC			0x48534C46	/* 'FLSH' */
 #define NVRAM_VERSION		1