x86/early_printk: Remove unused includes

After

  1bd187de ("x86, intel-mid: remove Intel MID specific serial support")

the Intel MID header is not needed anymore.

After

  69c1f396 ("efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation")

the EFI headers are not needed anymore.

Remove the respective includes.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200326175415.8618-1-andriy.shevchenko@linux.intel.com