MdeModulePkg: Update DBsize in SNP GetStatus command.

MdeModulePkg: Update DBsize in SNP GetStatus command.

Update the DBsize in GetStatus command to let UNDI return an array of recycled
buffers. This is to make the loop at the end of PxeGetStatus() useful and to
prevent buffer overflow with some non-conformant UNDI drivers which not check
the value of the input DBsize in UNDI GetStatus command.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Fu Siyuan <siyuan.fu@intel.com>
Reviewed-by: Sriram Subramanian <sriram-s@hpe.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ye Ting <ting.ye@intel.com>