scsi: ufs: rockchip,rk3576-ufshc: dt-bindings: Add new mphy reset item

scsi: ufs: rockchip,rk3576-ufshc: dt-bindings: Add new mphy reset item

Add the mphy reset property to the devicetree bindings for the Rockchip
RK3576 UFS host controller. The mphy reset signal is used to reset the
physical adapter. Resetting other components while leaving the mphy unreset
may occasionally prevent the UFS controller from successfully linking up
with the device.

This addresses an intermittent hardware bug where the UFS link fails to
establish under specific timing conditions with certain chips. While
difficult to reproduce initially, this issue was consistently observed in
downstream testing and requires explicit mphy reset control for full
stability.

Although this change increases the maxItems for resets and adds a new entry
(which technically alters the binding ABI), it does not break compatibility
for existing Linux systems. The driver uses
devm_reset_control_array_get_exclusive() to manage resets, allowing it to
function correctly with both older Device Trees (without the mphy entry)
and newer ones.

Fixes: d90e92023771 ("scsi: ufs: dt-bindings: Document Rockchip UFS host controller")
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://patch.msgid.link/1773368467-109650-1-git-send-email-shawn.lin@rock-chips.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>