Rename all i.MX6 pad declarations to MX6_PAD_x, so a board
may support either i.MX6Quad/Dual (MX6Q) or i.MX6Dual-Lite/Solo
(MX6DL) by including the proper header.
Boards mx6qarm2, mx6qsabreauto, mx6qsabrelite, and mx6qsabresd
only support MX6Q, so they include mx6q_pins.h.
Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
