[PATCH v7 5/6] mountmgr.sys: Add support for volume information queries.

[Erich E. Hoover]

This patch allows the mountmgr to handle the volume information
request IRP, allowing volume information to be queried from the
mountmgr by ntdll.

v7: No change
v6: Have harddisk_query_volume return the same status as the IoStatus.
v5: No change
v4: Reordered (no content change)
v3: Use SystemBuffer instead of UserBuffer (see
8e98dcd42e13bfeb5a2397ff9bf1c7f63c224e23)
v2: Per Zeb's request, now storing the volume with the disk_device so
that the lookup doesn't require a search.

Best,
Erich

[Zebediah Figura (she/her)]

Signed-off-by: Zebediah Figura