siemens/nc_fpga: Fix wrong type cast

As "var" is not a pointer but a variable there is no need to cast it to
a pointer before using the value.

Change-Id: I7f8e3ceadaa4301c50c5f5480cccab2be904aa9a
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/20572
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

src/drivers/siemens/nc_fpga/nc_fpga.c

@@ -28,7 +28,7 @@
 { \
 	uint32_t var; \
 	if (hwilib_get_field(src, (uint8_t *)&var, sizeof(var))) \
-		dst = *((typeof(dst) *)var); \
+		dst = ((typeof(dst))var); \
 }
 
 static void init_temp_mon (void *base_adr)