Drivers: hv: vss: Operation timeouts should match host expectation

Increase the timeout of backup operations. When system is under I/O load,
it needs more time to freeze. These timeout values should also match the
host timeout values more closely.

Signed-off-by: Alex Ng <alexng@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>