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.

MFC after:	2 days

sys/dev/mfi/mfi.c

@@ -3773,12 +3773,15 @@ mfi_timeout(void *data)
 				MFI_PRINT_CMD(cm);
 				MFI_VALIDATE_CMD(sc, cm);
 				/*
-				 * Fail the command instead of leaving it on
-				 * the queue where it could remain stuck forever
+				 * While commands can get stuck forever we do
+				 * not fail them as there is no way to tell if
+				 * the controller has actually processed them
+				 * or not.
+				 *
+				 * In addition its very likely that force
+				 * failing a command here would cause a panic
+				 * e.g. in UFS.
 				 */
-				mfi_remove_busy(cm);
-				cm->cm_error = ETIMEDOUT;
-				mfi_complete(sc, cm);
 				timedout++;
 			}
 		}