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/kernel/auxio_32.c b/arch/sparc/kernel/auxio_32.c
index 35f4883..8505e0a 100644
--- a/arch/sparc/kernel/auxio_32.c
+++ b/arch/sparc/kernel/auxio_32.c
@@ -121,7 +121,7 @@
 	node = prom_searchsiblings(node, "obio");
 	node = prom_getchild(node);
 	node = prom_searchsiblings(node, "power");
-	if (node == 0 || node == -1)
+	if (node == 0 || (s32)node == -1)
 		return;
 
 	/* Map the power control register. */