lib: Changes to avoid warnings during compilation

Changes to avoid warnings for enabling Werror flag in LK

Change-Id: I893ae71ef4ebd54faf1c3bed1d2080d9d733d418
diff --git a/lib/libfdt/fdt_ro.c b/lib/libfdt/fdt_ro.c
index 02b6d68..1e6b2e7 100644
--- a/lib/libfdt/fdt_ro.c
+++ b/lib/libfdt/fdt_ro.c
@@ -85,7 +85,7 @@
 {
 	const char *p = fdt_string(fdt, stroffset);
 
-	return (strlen(p) == len) && (memcmp(p, s, len) == 0);
+	return (strlen(p) == (size_t)len) && (memcmp(p, s, len) == 0);
 }
 
 int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size)
@@ -494,7 +494,7 @@
 {
 	int offset;
 
-	if ((phandle == 0) || (phandle == -1))
+	if ((phandle == 0))
 		return -FDT_ERR_BADPHANDLE;
 
 	FDT_CHECK_HEADER(fdt);