kernel: sweep — usb2phy port (USB host up) + saradc data port

usb2phy: ported the RV1106 inno-usb2 phy config to 6.18 (rv1106_usb2phy_cfg;
fields map 1:1 except utmi_iddig->utmi_id and chg_mode->opmode; 5.10-only
iddig_output/en/bvalid_grf_sel dropped; phy_tuning left off, guarded so safe).
With PHY_ROCKCHIP_INNO_USB2=y + the u2phy/usbdrd/dwc3 DT enabled, verified on
warden-c8a3: the DWC3 comes up as xhci-hcd @ 0xffb00000 — USB host works. eth0
gadget just needs dr_mode=peripheral.

saradc: added rv1106_saradc_data (2-ch v2, matches the vendor) + the native
compatible. Driver now matches; probe still returns -22 (a clk-rate/setup detail,
not the data) — TODO.

Also captured: the growing board dts (USB nodes), the port fragments under usb/
and adc/. DRIVER-PARITY.md updated: ~14 drivers now at parity on 6.18.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017wB8KB3MMQztRDXCMCkPrf

kernel/rv1106-enablement/adc/rv1106_saradc_data.c.frag

@@ -0,0 +1,13 @@
+/* RV1106: a 2-channel v2 SARADC (ported from the vendor driver). */
+static const struct iio_chan_spec rockchip_rv1106_saradc_iio_channels[] = {
+	SARADC_CHANNEL(0, "adc0", 10),
+	SARADC_CHANNEL(1, "adc1", 10),
+};
+
+static const struct rockchip_saradc_data rv1106_saradc_data = {
+	.channels = rockchip_rv1106_saradc_iio_channels,
+	.num_channels = ARRAY_SIZE(rockchip_rv1106_saradc_iio_channels),
+	.clk_rate = 1000000,
+	.start = rockchip_saradc_start_v2,
+	.read = rockchip_saradc_read_v2,
+};