of/flattree: fix of_flat_dt_is_compatible() to match the full compatible string

With the current string comparison, a device tree compatible of "foo-bar"
would match as compatible with a driver looking for "foo".  This patch
fixes the function to use the of_compat_cmp() macro so that it does the
right thing on all platforms (If sparc ever uses this code, it will still
want the strncasecmp() behaviour).
Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

drivers/of/fdt.c

@@ -169,7 +169,7 @@ int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
 	if (cp == NULL)
 		return 0;
 	while (cplen > 0) {
-		if (strncasecmp(cp, compat, strlen(compat)) == 0)
+		if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
 			return 1;
 		l = strlen(cp) + 1;
 		cp += l;