ArmVirtPkg: disable deprecated interfaces

ArmVirtPkg: disable deprecated interfaces

At this point no code in ArmVirtPkg (and apparently no code outside of
ArmVirtPkg that the ArmVirt binaries depend on) uses the deprecated APIs,
so we can disable them in the common platform DSC include file:

BaseLib:
- StrCpy
- StrnCpy
- StrCat
- StrnCat
- UnicodeStrToAsciiStr
- AsciiStrCpy
- AsciiStrnCpy
- AsciiStrCat
- AsciiStrnCat
- AsciiStrToUnicodeStr

PcdLib:
- PcdSet8
- PcdSet16
- PcdSet32
- PcdSet64
- PcdSetPtr
- PcdSetBool
- PcdSetEx8
- PcdSetEx16
- PcdSetEx32
- PcdSetEx64
- PcdSetExPtr
- PcdSetExBool

UefiLib:
- GetVariable
- GetEfiGlobalVariable

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> # RVCT
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>