MdeModulePkg/NvmExpressDxe: Clear NSID to 0 for sanitize command

A purge erase operation on NVMe devices using the MediaSanitize
(MediaPurge) protocol fails with Status Code 02h (Invalid Field
in Command).

According to NVMe specification revision 1.4c, the Sanitize
command (OpCode 84h) does not use the NSID field (Section 5,
Figure 142). For commands that do not use NSID, the field must
be cleared to 0 as defined in Section 4.2, Figure 106.

Clear NSID to 0 before issuing the Sanitize command to ensure
spec compliance and prevent command failure.

Signed-off-by: Shabab Alam <shabalam@qti.qualcomm.com>