gpio: Introduce new mcux gpio driver

Adds a new mcux gpio driver that can be used for k64 and other Kinetis
SoCs. This driver uses mcux CMSIS register accesses to the GPIO and PORT
modules. Some of the logic from the k64 gpio driver was reused and
refactored (mainly flag parsing and callback handling).

Jira: ZEP-1394
Change-Id: If5e9390861c181ec555dce6569b14debb729526a
Signed-off-by: Maureen Helm <maureen.helm@nxp.com>