Fix build problems on i386-ieee1275 and *-efi (introduced by vga_text
split).
* include/grub/i386/pc/console.h: Include `<grub/i386/vga_common.h>'.
(grub_console_cur_color, grub_console_real_putchar)
(grub_console_putchar, grub_console_getcharwidth, grub_console_getwh)
(grub_console_setcolorstate, grub_console_setcolor)
(grub_console_getcolor): Move from here ...
* include/grub/i386/vga_common.h: ... to here (new file).
* term/i386/pc/vga_text.c: Replace `<grub/machine/console.h>' with
`<grub/i386/vga_common.h>' and `<grub/cpu/io.h>' with
`<grub/i386/io.h>'.
* term/i386/vga_common.c: Replace `<grub/machine/console.h>' with
`<grub/i386/vga_common.h>'.
