MFC r252471:
Remove forced timeout of in-flight commands from mfi_timeout.

While this prevents commands getting stuck forever there is no way to guarantee
that data from the command hasn't been committed to the device.

In addition older mfi firmware has a bug that would cause the controller to
frequently stall IO for over our timeout value, which when combined with
a forced timeout often resulted in panics in UFS; which would otherwise be
avoided when the command eventually completed if left alone.

For reference this timeout issue is resolved in Dell FW package 21.2.1-0000.
Fixed FW package version for none Dell controller will likely vary.