ArmPkg: Add missing library headers to ArmPkg.dec

ArmPkg: Add missing library headers to ArmPkg.dec

Some library headers are missing/incorrect in ArmPkg.dec.
This makes the 'LibraryClassCheck' CI test fail. This patch
adds/corrects them.

According to .pytool/Readme about the 'LibraryClassCheck' test:
This test scans at all library header files found in the
`Library` folders in all of the package's declared include
directories and ensures that all files have a matching
LibraryClass declaration in the DEC file for the package.

Fixes: https://bugzilla.tianocore.org/show_bug.cgi?id=3254
Fixes: https://bugzilla.tianocore.org/show_bug.cgi?id=3258
Cc: Bret Barkelew <bret.barkelew@microsoft.com>
Cc: Sean Brogan <sean.brogan@microsoft.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Reviewed-by: Bret Barkelew <bret.barkelew@microsoft.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>