IntelSiliconPkg MicrocodeUpdateDxe: Fix (ExtendedTableLength & 0x3)!=0

The first 48 bytes contain the microcode update header.
DataSize must be a multiple of DWORDs.
TotalSize is always a multiple of 1024.
Both size of CPU_MICROCODE_EXTENDED_TABLE_HEADER and
CPU_MICROCODE_EXTENDED_TABLE are multiple of DWORDs.

So (ExtendedTableLength & 0x3)!=0 should be
(ExtendedTableLength & 0x3)==0.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Rangasai V Chaganty <rangasai.v.chaganty@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Rangasai V Chaganty <rangasai.v.chaganty@intel.com>