iio: temperature: mlx90632: Add error handling for devm_pm_runtime_enable()

This call can fail so handling is necessary even if it is very unlikely.

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1527134 ("Error handling issues")
Fixes: 2aebc223 ("iio: temperature: mlx90632 Add runtime powermanagement modes")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-off-by: Crt Mori <cmo@melexis.com>
Link: https://lore.kernel.org/r/20221105125108.383193-2-jic23@kernel.org