Platform: Remove warning in Musca-S1 ioctl function

Remove an assignment which is not needed in a Musca-S1 ioctl
function to get rid of a compiler warning.

Signed-off-by: Antonio de Angelis <antonio.deangelis@arm.com>
Change-Id: I737d08a97f194addd735ebccae46a550aa2c83eb
diff --git a/platform/ext/target/arm/musca_s1/services/src/tfm_platform_system.c b/platform/ext/target/arm/musca_s1/services/src/tfm_platform_system.c
index 2160cc2..089a56e 100644
--- a/platform/ext/target/arm/musca_s1/services/src/tfm_platform_system.c
+++ b/platform/ext/target/arm/musca_s1/services/src/tfm_platform_system.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Arm Limited. All rights reserved.
+ * Copyright (c) 2018-2022, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *
@@ -36,7 +36,6 @@
                      const psa_outvec *out_vec)
 {
     struct tfm_pin_service_args_t *args;
-    uint32_t *result;
     enum gpio_altfunc_t altfunc;
     enum pinmode_select_t pin_mode;
 
@@ -46,7 +45,7 @@
     }
 
     args = (struct tfm_pin_service_args_t *)in_vec->base;
-    result = (uint32_t *)out_vec->base;
+
     switch (args->type) {
     case TFM_PIN_SERVICE_TYPE_SET_ALTFUNC:
         altfunc = (enum gpio_altfunc_t)args->u.set_altfunc.alt_func;