ShellPkg: Add revision check for DSDT Header on Arm

ShellPkg: Add revision check for DSDT Header on Arm

Bugzilla: 3995 (https://bugzilla.tianocore.org/show_bug.cgi?id=3995)

ACPI 6.4 spec states that if the revision field in the DSDT header is less
than 2, then all integers are restricted in width to 32 bits, including in
SSDTs.

Arm Base boot requirements state that platforms must conform to ACPI 6.3
or later, and that legacy tables are not supported.

Adds a check for this field and raise warning if revision is less
than 2 on arm.

Signed-off-by: Edward Pickup <edward.pickup@arm.com>
Reviewed-by: Zhichao Gao <zhichao.gao@intel.com>