staging:iio:spear_adc: Add dependency on HAS_IOMEM
staging:iio:spear_adc: Add dependency on HAS_IOMEM

On archs like S390 or um this driver cannot build nor work.
Make it depend on HAS_IOMEM to bypass build failures.

drivers/staging/iio/adc/spear_adc.c: In function ‘spear_adc_probe’:
drivers/staging/iio/adc/spear_adc.c:393:2: error: implicit declaration of function ‘iounmap’ [-Werror=implicit-function-declaration

Signed-off-by: Richard Weinberger <320bca71fc381a4a025636043ca86e734e31cf8b@nod.at>
Signed-off-by: Jonathan Cameron <09f65b71b7655725897b2fd41a09a0cefe2e1ace@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs