MdePkg: Increase EFI_RESOURCE_MAX_MEMORY_TYPE

MdePkg: Increase EFI_RESOURCE_MAX_MEMORY_TYPE

RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3937

BZ3937_EFI_RESOURCE_MEMORY_UNACCEPTED is defined for unaccepted memory.
But this defitinion has not been officially in the PI spec. Base
on the code-first we define EFI_RESOURCE_MEMORY_UNACCEPTED at
MdeModulePkg/Include/Pi/PrePiHob.h and update EFI_RESOURCE_MAX_MEMORY_TYPE
to 8. After BZ3937_EFI_RESOURCE_MEMORY_UNACCEPTED is officially published
in PI spec, we will re-visit here.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Signed-off-by: Min Xu <min.m.xu@intel.com>