x86/efi: Remove unused EFI_UV1_MEMMAP code

With UV1 support removed, EFI_UV1_MEMMAP is no longer used.

Signed-off-by: Steve Wahl <steve.wahl@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lkml.kernel.org/r/20200713212956.019149227@hpe.com