src: Remove unused 'include <string.h>'

Change-Id: I2a94c3b6282e9915fd2b8136b124740c8a7b774c
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36082
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/device/oprom/realmode/x86_interrupts.c

@@ -15,7 +15,6 @@
 #include <console/console.h>
 #include <device/pci.h>
 #include <device/pci_ops.h>
-#include <string.h>
 
 /* we use x86emu's register file representation */
 #include <x86emu/regs.h>

src/device/oprom/x86emu/sys.c

@@ -50,7 +50,6 @@
 #ifdef IN_MODULE
 #include "xf86_ansic.h"
 #else
-#include <string.h>
 #endif
 /*------------------------- Global Variables ------------------------------*/
 

src/device/oprom/x86emu/x86emui.h

@@ -72,7 +72,6 @@
 #ifdef IN_MODULE
 #include <xf86_ansic.h>
 #else
-#include <string.h>
 #endif
 /*--------------------------- Inline Functions ----------------------------*/
 

src/device/oprom/yabel/compat/functions.c

@@ -36,7 +36,6 @@
  */
 
 #include <types.h>
-#include <string.h>
 #include <device/device.h>
 #include "../debug.h"
 #include "../biosemu.h"