BaseTools/EfiRom: supply missing machine type lookup strings

BaseTools/EfiRom: supply missing machine type lookup strings

"EfiRom --dump" does not recognize the 0x8664 machine type:

>   EFI ROM header contents
>     EFI Signature          0x0EF1
>     Compression Type       0x0001 (compressed)
>     Machine type           0x8664 (unknown)
>     Subsystem              0x000B (EFI boot service driver)
>     EFI image offset       0x0050 (@0xF650)

Add lookup strings for the remaining EFI_IMAGE_MACHINE_* numeric macros
that can be found in
"BaseTools/Source/C/Include/IndustryStandard/PeImage.h". The strings
follow Table 12. "UEFI Image Types" from the UEFI v2.6 spec.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>