MdePkg/MdeModulePkg: Move AML_NAME_SEG_SIZE definition

MdePkg/MdeModulePkg: Move AML_NAME_SEG_SIZE definition

A NameSeg is made 4 chars.
Cf. ACPI 6.4 s20.2.2 "Name Objects Encoding":
NameSeg := <leadnamechar namechar namechar namechar>
Notice that NameSegs shorter than 4 characters are filled
with trailing underscores (‘_’s).

AML_NAME_SEG_SIZE is currently defined in:
- DynamicTablesPkg/Library/Common/AmlLib/AmlDefines.h
- MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiSdt.h
Since the value can be inferred from the ACPI specification
and to avoid multiple definitions, move it to
MdePkg/Include/IndustryStandard/

Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>