DynamicTablesPkg: Minor updates and fix typos

DynamicTablesPkg: Minor updates and fix typos

This patch was originally merged in edk2 master at
07f4e26eb6fe5203028ecfe9bad90d3b67dc72c8. However, this was
later reverted at 4c20a7913333fdbd3b4c83dba060fefa84027313
as it was merged during the Soft Feature Freeze for
edk2-stable201903.

Resubmitting this patch as the edk2 merge window is now open.

Minor updates to comments and typo fixes. Also removed
unused structure CM_ARM_CPU_INFO_LIST.

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Alexei Fedorov <alexei.fedorov@arm.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Alexei Fedorov <alexei.fedorov@arm.com>