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_32.c b/arch/sparc/prom/init_32.c
index d342dba..0a601b3 100644
--- a/arch/sparc/prom/init_32.c
+++ b/arch/sparc/prom/init_32.c
@@ -60,7 +60,7 @@
 	prom_nodeops = romvec->pv_nodeops;
 
 	prom_root_node = prom_getsibling(0);
-	if((prom_root_node == 0) || (prom_root_node == -1))
+	if ((prom_root_node == 0) || ((s32)prom_root_node == -1))
 		prom_halt();
 
 	if((((unsigned long) prom_nodeops) == 0) ||