x86: get_bios_ebda() requires asm/io.h

include <asm/io.h> for phys_to_virt()
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

include/asm-x86/bios_ebda.h

 #ifndef _MACH_BIOS_EBDA_H
 #define _MACH_BIOS_EBDA_H
 
+#include <asm/io.h>
+
 /*
  * there is a real-mode segmented pointer pointing to the
  * 4K EBDA area at 0x40E.