sparc: explicitly cast negative phandle checks to s32

When we switched sparc from using 'int's to 'phandle's (which is a u32), we
neglected to do anything with the various checks for -1.  For those tests,
explicitly cast the phandles to s32.

Signed-off-by: Andres Salomon <dilinger@queued.net>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/arch/sparc/prom/init_64.c b/arch/sparc/prom/init_64.c
index 3ff911e..200528b 100644
--- a/arch/sparc/prom/init_64.c
+++ b/arch/sparc/prom/init_64.c
@@ -35,14 +35,14 @@
 	prom_cif_init(cif_handler, cif_stack);
 
 	prom_chosen_node = prom_finddevice(prom_chosen_path);
-	if (!prom_chosen_node || prom_chosen_node == -1)
+	if (!prom_chosen_node || (s32)prom_chosen_node == -1)
 		prom_halt();
 
 	prom_stdin = prom_getint(prom_chosen_node, "stdin");
 	prom_stdout = prom_getint(prom_chosen_node, "stdout");
 
 	node = prom_finddevice("/openprom");
-	if (!node || node == -1)
+	if (!node || (s32)node == -1)
 		prom_halt();
 
 	prom_getstring(node, "version", prom_version, sizeof(prom_version));