[POWERPC] Fix compiler warning message on get_property call

This fixes the warning message from the return value of function
get_property(), by making sure that the variable that receives the
value is marked as const.

Signed-off-by: Roy Zang <[e-mail]>

--
Signed-off-by: Paul Mackerras <[e-mail]>

arch/powerpc/sysdev/tsi108_dev.c

···
 	tsi = of_find_node_by_type(NULL, "tsi-bridge");
 	if (tsi) {
 		unsigned int size;
-		void *prop = get_property(tsi, "reg", &size);
+		const void *prop = get_property(tsi, "reg", &size);
 		tsi108_csr_base = of_translate_address(tsi, prop);
 		of_node_put(tsi);
 	};
···
 		hw_info tsi_eth_data;
 		unsigned int *id;
 		unsigned int *phy_id;
-		void *mac_addr;
+		const void *mac_addr;
 		phandle *ph;
 
 		memset(r, 0, sizeof(r));