usb: gadget: tegra-xudc: Add handling for BLCG_COREPLL_PWRDN

usb: gadget: tegra-xudc: Add handling for BLCG_COREPLL_PWRDN

The COREPLL_PWRDN bit in the BLCG register must be set when the XUSB
device controller is powergated and cleared when it is unpowergated.
If this bit is not explicitly controlled, the core PLL may remain in an
incorrect power state across suspend/resume or ELPG transitions.
Therefore, update the driver to explicitly control this bit during
powergate transitions.

Fixes: 49db427232fe ("usb: gadget: Add UDC driver for tegra XUSB device mode controller")
Cc: stable <stable@kernel.org>
Signed-off-by: Haotien Hsu <haotienh@nvidia.com>
Signed-off-by: Wayne Chang <waynec@nvidia.com>
Link: https://patch.msgid.link/20260123173121.4093902-1-waynec@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>