DynamicTablesPkg: Add AmlSetRdListCheckSum()

DynamicTablesPkg: Add AmlSetRdListCheckSum()

Lists of Resource Data elements end with an EndTag (most of the time).
This function finds the EndTag (if present) in a list of Resource Data
elements and sets the checksum.

ACPI 6.4, s6.4.2.9 "End Tag":
"This checksum is generated such that adding it to the sum of all the data
bytes will produce a zero sum."
"If the checksum field is zero, the resource data is treated as if the
checksum operation succeeded. Configuration proceeds normally."

Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>