staging: skein: Remove useless initialisation

Remove intialisation of a variable that is immediately reassigned.

The semantic patch used to find this is:

// <smpl>
@@
type T;
identifier x;
constant C;
expression e;
@@

T x
- = C
 ;
x = e;
// </smpl>

Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/skein/skein_api.c

@@ -127,7 +127,7 @@ int skein_mac_init(struct skein_ctx *ctx, const u8 *key, size_t key_len,
 void skein_reset(struct skein_ctx *ctx)
 {
 	size_t x_len = 0;
-	u64 *x = NULL;
+	u64 *x;
 
 	/*
 	 * The following two lines rely of the fact that the real Skein