intel_minnow_max: Added platform definition

Signed-off-by: Henry Bruce <henry.bruce@intel.com>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
gpio.c: check that real gpio did initialise correctly

On platforms without muxing perform a little more checking when the 'real'
linux/sysfs gpio is opened. We don't expect this to fail but on platforms where
the linux gpios can be changed depending on pinctrl/bios configuration this
might not always be the case.

Signed-off-by: Henry Bruce <henry.bruce@intel.com>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
hellomraa.c: Extended sample to display detected platform.

Signed-off-by: Henry Bruce <henry.bruce@intel.com>
blink_onboard.c: Added Minnow Max support

Signed-off-by: Henry Bruce <henry.bruce@intel.com>
pwm.c: Must write period before duty_cycle to avoid sysfs error

Signed-off-by: Henry Bruce <henry.bruce@intel.com>
oe-sdk_cross.cmake: 'make install' now targets oe sysroot

Signed-off-by: Henry Bruce <henry.bruce@intel.com>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
mraa.c: fix char count in board_name

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>