Configure WaRP ECSPI2 interface

Add pads and pad configuration for ECSPI2 interface that is used for
FXOS8700 sensor.

Signed-off-by: Jacob Postman <jacob@revolution-robotics.com>
Signed-off-by: Diego Rondini <diego.rondini@kynetics.it>

Conflicts:
	arch/arm/mach-mx6/board-mx6sl_warp.c
Fixed chip ID reporting in FXOS8700 driver

Fixed bug in FXOS8700 driver where chip ID would always be reported as
0x0 in an error message when chip id read fails or returns unexpected
value during FXOS87000 initialization.

Signed-off-by: Jacob Postman <jacob@revolution-robotics.com>