scsi: storvsc: fix memory leak on ring buffer busy

scsi: storvsc: fix memory leak on ring buffer busy

BugLink: http://bugs.launchpad.net/bugs/1720154
commit 0208eeaa650c5c866a3242201678a19e6dc4a14e upstream.

When storvsc is sending I/O to Hyper-v, it may allocate a bigger buffer
descriptor for large data payload that can't fit into a pre-allocated
buffer descriptor. This bigger buffer is freed on return path.

If I/O request to Hyper-v fails due to ring buffer busy, the storvsc
allocated buffer descriptor should also be freed.

[mkp: applied by hand]

Fixes: be0cf6ca301c ("scsi: storvsc: Set the tablesize based on the information given by the host")
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>