[PATCH rtems / rtems-libbsd] Updates for imx BSP

[Christian Mauderer]

Hello,

this two patch sets add fixes and improvements for the imx BSP:

In RTEMS:
- A small GPIO driver is added. It is used in the SPI driver to
  fix a wrong behaviour of the chip select lines that can't be fixed if
  the chip selects are controlled by the SPI controller instead of
  GPIOs.
- The copy of the FDT is now cache aligned if a cache alignment is given
  for the CPU.

In libbsd:
- Some dead code is eliminated.
- The imx GPIO driver is used instead of the ported FreeBSD one.
  Otherwise the FreeBSD driver will re-initialize the GPIOs.
- Some caching problems are fixed.

Both patch sets are intended for the master branches. In theory we could
think about backporting them to 5 because some bugs are fixed. But I'm
not sure whether the GPIO counts as a new feature or not.

Best regards

Christian