Platform: Fix typing issue for IAR

Can't perform pointer arithmetic on void *.

Signed-off-by: TTornblom <thomas.tornblom@iar.com>
Change-Id: I0918b934f8a063e392e93c1277a74ea81c22a4e9
diff --git a/platform/ext/target/musca_a/CMSIS_Driver/Driver_QSPI_Flash.c b/platform/ext/target/musca_a/CMSIS_Driver/Driver_QSPI_Flash.c
index 627d722..3a1845c 100644
--- a/platform/ext/target/musca_a/CMSIS_Driver/Driver_QSPI_Flash.c
+++ b/platform/ext/target/musca_a/CMSIS_Driver/Driver_QSPI_Flash.c
@@ -218,7 +218,7 @@
     if (extra_bytes != 0) {
         err = mt25ql_command_read(ARM_FLASH0_DEV.dev, addr + cnt, &extra_word,
                                 data_width_byte[DriverCapabilities.data_width]);
-        memcpy(data + cnt, &extra_word, extra_bytes);
+        memcpy((char *) data + cnt, &extra_word, extra_bytes);
     }
 
     ARM_FLASH0_STATUS.busy = DRIVER_STATUS_IDLE;