uml: fix compile warning

This fixes:
incompatible pointer type:  => 89
       arch/um/kernel/exec.c: warning: passing argument 2 of 'execve1' from
incompatible pointer type:  => 69, 85
       arch/um/kernel/exec.c: warning: passing argument 3 of 'execve1' from
incompatible pointer type:  => 69, 85

which was introduced by d7627467b7a8d ("Make do_execve() take a const
filename pointer")

Signed-off-by: Richard Weinberger <richard@nod.at>
Cc: David Howells <dhowells@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/kernel/exec.c b/arch/um/kernel/exec.c
index cd145ed..49b5e1e 100644
--- a/arch/um/kernel/exec.c
+++ b/arch/um/kernel/exec.c
@@ -62,7 +62,7 @@
 	return error;
 }
 
-long um_execve(const char *file, char __user *__user *argv, char __user *__user *env)
+long um_execve(const char *file, const char __user *const __user *argv, const char __user *const __user *env)
 {
 	long err;
 
@@ -72,8 +72,8 @@
 	return err;
 }
 
-long sys_execve(const char __user *file, char __user *__user *argv,
-		char __user *__user *env)
+long sys_execve(const char __user *file, const char __user *const __user *argv,
+		const char __user *const __user *env)
 {
 	long error;
 	char *filename;