phy: spacemit: support K1 USB2.0 PHY controller

phy: spacemit: support K1 USB2.0 PHY controller

The SpacemiT K1 SoC includes three USB ports:

- One USB2.0 OTG port
- One USB2.0 host-only port
- One USB3.0 port with an integrated USB2.0 DRD interface

Each of these ports is connected to a USB2.0 PHY responsible for USB2
transmission.

This commit adds support for the SpacemiT K1 USB2.0 PHY, which is
compliant with the USB 2.0 specification and supports both 8-bit 60MHz
and 16-bit 30MHz parallel interfaces.

Signed-off-by: Ze Huang <huang.ze@linux.dev>
Tested-by: Aurelien Jarno <aurelien@aurel32.net>
Tested-by: Junzhong Pan <panjunzhong@linux.spacemit.com>
Link: https://patch.msgid.link/20251017-k1-usb2phy-v6-2-7cf9ea2477a1@linux.dev
Signed-off-by: Vinod Koul <vkoul@kernel.org>