Randconfig testing found compile errors in drivers/of/unittest.c if
CONFIG_GPIOLIB is not set because CONFIG_OF_GPIO depends on
CONFIG_GPIOLIB. Make the gpio overlay test depend on CONFIG_OF_GPIO.
No code is modified, it is only moved to a different location and
protected with #ifdef CONFIG_OF_GPIO. An empty
of_unittest_overlay_gpio() is added in the #else.
Fixes: f4056e705b ("of: unittest: add overlay gpio test to catch gpio hog problem")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Frank Rowand <frank.rowand@sony.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Rob Herring <robh@kernel.org>