ArmPlatformPkg/ArmPlatformPkg.dsc: Add missing components

ArmPlatformPkg/ArmPlatformPkg.dsc: Add missing components

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2575

The following components are currently missing from the [Components]
section of ArmPlatformPkg.dsc:
  * ArmPlatformPkg/Library/HdLcd/HdLcd.inf
  * ArmPlatformPkg/Library/PL111Lcd/PL111Lcd.inf

This commit includes the components in the package DSC build.

Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>