iio: accel: mma9551/3: Balance untime pm + use pm_runtime_resume_and_get()

Both these drivers call pm_runtime_put_no_idle() when the reference
count should already be zero as there is no matching get()

Whilst here use pm_runtime_resume_and_get() rather than open coding.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/20210509113354.660190-7-jic23@kernel.org