MdeModulePkg/NonDiscoverablePciDevice: Remove the redundant check

MdeModulePkg/NonDiscoverablePciDevice: Remove the redundant check

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1422

if (Attributes) {
  if ((Attributes & (~(DEV_SUPPORTED_ATTRIBUTES))) != 0) {
    return EFI_UNSUPPORTED;
  }
}
In above code block,
"If ((Attributes & (~(DEV_SUPPORTED_ATTRIBUTES))) != 0)" is TRUE,
the Attributes must be not 0. So we can remove the redundant
check "if (Attributes)".

Cc: Vladimir Olovyannikov <vladimir.olovyannikov@broadcom.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao Wu <hao.a.wu@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>