soc/intel/xeon_sp/gnr/soc_iio: Remove unused <string.h>

Change-Id: I8d4500edaa0739921831a3b04131046599c35a87
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82618
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>
Reviewed-by: Shuo Liu <shuo.liu@intel.com>

src/soc/intel/xeon_sp/gnr/soc_iio.c

@@ -1,7 +1,6 @@
  /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <soc/iio.h>
-#include <string.h>
 
 #include <fsp/util.h>
 #include <IioPcieConfigUpd.h>