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>
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index d61fda8..dc876cb 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -169,7 +169,7 @@
 	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;