x86: Move available drivers into drivers/legacy_pc/

All drivers implemented so far are for chips which are only available
on legacy x86 PCs. This commit moves them into a more appropriate folder,
also making the cpu/x86/drivers/ folder ready for other x86 based SoCs.

cpu/x86/Makefile.x86

@@ -1,4 +1,4 @@
-CONTIKI_CPU_DIRS = . drivers
+CONTIKI_CPU_DIRS = . drivers/legacy_pc
 
 CONTIKI_SOURCEFILES += gdt.c helpers.S idt.c cpu.c rtc.c pit.c pic.c
 

cpu/x86/drivers/legacy_pc/pic.c

@@ -28,7 +28,7 @@
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include "drivers/pic.h"
+#include "drivers/legacy_pc/pic.h"
 
 #define PIC_ACK 0x20
 

cpu/x86/drivers/legacy_pc/pit.c

@@ -30,8 +30,8 @@
 
 #include <math.h>
 
-#include "drivers/pic.h"
-#include "pit.h"
+#include "drivers/legacy_pc/pic.h"
+#include "drivers/legacy_pc/pit.h"
 #include "helpers.h"
 #include "interrupt.h"
 

cpu/x86/drivers/legacy_pc/rtc.c

@@ -28,8 +28,8 @@
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include "drivers/rtc.h"
-#include "drivers/pic.h"
+#include "drivers/legacy_pc/rtc.h"
+#include "drivers/legacy_pc/pic.h"
 #include "helpers.h"
 #include "interrupt.h"
 

platform/galileo/core/sys/clock.c

@@ -32,7 +32,7 @@
 #include "sys/etimer.h"
 
 #include "contiki-conf.h"
-#include "drivers/rtc.h"
+#include "drivers/legacy_pc/rtc.h"
 
 #if CLOCK_CONF_SECOND == 2
 #define FREQ   RTC_2_HZ

platform/galileo/core/sys/rtimer-arch.c

@@ -31,7 +31,7 @@
 #include "sys/rtimer.h"
 
 #include "contiki-conf.h"
-#include "drivers/pit.h"
+#include "drivers/legacy_pc/pit.h"
 
 static volatile rtimer_clock_t tick_count = 0;
 static rtimer_clock_t trigger = UINT64_MAX;