mb/lenovo/thinkcentre_a58/acpi_tables: Remove unneeded includes

Change-Id: I8f8e43d0f146b1050eb68da197504441b60a4120
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38374
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/mainboard/lenovo/thinkcentre_a58/acpi_tables.c

@@ -14,7 +14,6 @@
  * GNU General Public License for more details.
  */
 
-#include <string.h>
 #include <southbridge/intel/i82801gx/nvs.h>
 
 void acpi_create_gnvs(global_nvs_t *gnvs)