Input: adi - remove redundant variable z

Variable z is being assigned a value that is never read, the
variable is redundant and can be removed.

Cleans up clang scan build warning:
drivers/input/joystick/adi.c:139:6: warning: Although the
value stored to 'z' is used in the enclosing expression,
the value is never actually read from 'z' [deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20220318002318.80519-1-colin.i.king@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/joystick/adi.c

@@ -123,7 +123,7 @@ static void adi_read_packet(struct adi_port *port)
 {
 	struct adi *adi = port->adi;
 	struct gameport *gameport = port->gameport;
-	unsigned char u, v, w, x, z;
+	unsigned char u, v, w, x;
 	int t[2], s[2], i;
 	unsigned long flags;
 
@@ -136,7 +136,7 @@ static void adi_read_packet(struct adi_port *port)
 	local_irq_save(flags);
 
 	gameport_trigger(gameport);
-	v = z = gameport_read(gameport);
+	v = gameport_read(gameport);
 
 	do {
 		u = v;