We have been combining imported mcux drivers into a flattened directory
structure to maximize driver reuse, but the introduction of additional
nxp soc families (lpc and imx) to zephyr has introduced driver naming
conflicts. This caused us to rename and modify imported files, such as
fsl_gpio.c/h, to make them unique across all three nxp soc families.
This makes updating the the mcux drivers complicated, especially for the
lpc family.
Reoganize the mcux drivers into soc family subfolders, so we can just
copy all the drivers from an mcux distribution (which is done on an
soc-basis) into the appropriate soc family folder. Undo all of the
naming changes that occurred when lpc and imx drivers were originally
imported. Undo the accidental squashing of the kinetis watchdog and dcdc
drivers that occurred when the imx drivers were introduced.
The drawback to this approach is that we have duplicate files when the
same hw ip modules exist in multiple soc families, however there are
only few cases where this occurs, such as fsl_lpuart and fsl_trng.
Signed-off-by: Maureen Helm <maureen.helm@nxp.com>