ShellPkg: acpiview: Remove duplicate ACPI structure size definitions

ShellPkg: acpiview: Remove duplicate ACPI structure size definitions

Remove duplicate Generic Address Structure (GAS) and ACPI table header
size definitions. Replace any dependencies with the definitions from
Acpi63.h.

AcpiParser.h redefines the size of Generic Address Structure (GAS) and
the ACPI table header. The motivation is to 'minimise any reference to
the EDK2 ACPI headers in an attempt to provide cross checking'. While
the redefined values are unlikely to change, redefinition causes
unnecessary maintenance overhead for acpiview.

In addition to this, EDK2 ACPI headers are referenced throughout the
entire project, so the assumption should be that the definitions in
these header files are correct.

Signed-off-by: Krzysztof Koch <krzysztof.koch@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Zhichao Gao <zhichao.gao@intel.com>