phy: qcom-qmp-ufs: Rename qmp_ufs_power_off

phy: qcom-qmp-ufs: Rename qmp_ufs_power_off

Rename qmp_ufs_disable to qmp_ufs_power_off to better represent its
functionality. Additionally, inline qmp_ufs_exit into qmp_ufs_power_off
function to preserve the functionality of .power_off.

There is no functional change.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Nitin Rawat <quic_nitirawa@quicinc.com>
Link: https://lore.kernel.org/r/20250526153821.7918-8-quic_nitirawa@quicinc.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>