Revert "serial: imx: initialized DMA w/o HW flow enabled"

Revert "serial: imx: initialized DMA w/o HW flow enabled"

This reverts commit 53e6c019a25a832cfdfd6d811db7726781c49b87.

According to some tests, SDMA support is broken at least for i.MX6 without
HW flow control. Different forms of data-corruption appear either with
the ROM firmware for the SDMA controller as well as when loading Freescale
provided SDMA firmware versions 1.1 or 3.1.

Signed-off-by: David Jander <david@protonic.nl>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>