iio: adc: ti-adc12138: Simplify with devm_clk_get_enabled()

iio: adc: ti-adc12138: Simplify with devm_clk_get_enabled()

Driver is getting clock and almost immediately enabling it, with the
devm_request_irq() as the only relevant code executed between, thus the
probe path and cleanups can be simplified with devm_clk_get_enabled().

Move devm_request_irq() earlier, so the interrupt handler will be
registered before clock is enabled.  This might be important in case
regulator supplies are enabled by other device driver and this device
raises interrupt immediately after clock sarts ticking.

The change does not reverse cleanup paths - first regulator will be
disabled, then clock and finally interrupt handler freed.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20250713-iio-clk-get-enabled-v1-1-70abc1f9ce6c@linaro.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>