efi_loader: Remove <common.h>

We largely do not need <common.h> in these files, so drop it. The only
exception here is that efi_freestanding.c needs <linux/types.h> and had
been getting that via <common.h>.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>