<linux/uaccess.h>: Fix copy_in_user() declaration

copy_in_user() copies data from user-space address @from to user-
space address @to. Hence declare both @from and @to as user-space
pointers.

Fixes: commit d597580d ("generic ...copy_..._user primitives")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

include/linux/uaccess.h

@@ -156,7 +156,7 @@ copy_to_user(void __user *to, const void *from, unsigned long n)
 }
 #ifdef CONFIG_COMPAT
 static __always_inline unsigned long __must_check
-copy_in_user(void __user *to, const void *from, unsigned long n)
+copy_in_user(void __user *to, const void __user *from, unsigned long n)
 {
 	might_fault();
 	if (access_ok(VERIFY_WRITE, to, n) && access_ok(VERIFY_READ, from, n))