scsi: ufs: exynos: Move phy calls to .exit() callback

scsi: ufs: exynos: Move phy calls to .exit() callback

ufshcd_pltfrm_remove() calls ufshcd_remove(hba) which in turn calls
ufshcd_hba_exit().

By moving the phy_power_off() and phy_exit() calls to the newly created
.exit callback they get called by ufshcd_variant_hba_exit() before
ufshcd_hba_exit() turns off the regulators. This is also similar flow to
the ufs-qcom driver.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Link: https://lore.kernel.org/r/20250319-exynos-ufs-stability-fixes-v2-6-96722cc2ba1b@linaro.org
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>