[MIPS] Alchemy: Fix wrong cast

Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/au1000/pb1100/init.c

@@ -53,7 +53,7 @@ void __init prom_init(void)
 
 	prom_argc = fw_arg0;
 	prom_argv = (char **) fw_arg1;
-	prom_envp = (int *) fw_arg3;
+	prom_envp = (char **) fw_arg3;
 
 	mips_machgroup = MACH_GROUP_ALCHEMY;
 	mips_machtype = MACH_PB1100;