mb/google/octopus/casta: Tune usb2eye setting

It needs to tune usb2eye setting for these ports:
 USB2[4] - type-c port
 USB2[6] - camera

BUG=b:122878632
BRANCH=octopus
TEST=built and passed usb2eye SI test

Change-Id: Iaa3adaab2f391e95730b141dc0237ca62c459e5a
Signed-off-by: Seunghwan Kim <sh_.kim@samsung.com>
Reviewed-on: https://review.coreboot.org/c/31359
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Justin TerAvest <teravest@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/octopus/variants/casta/overridetree.cb

@@ -1,4 +1,22 @@
 chip soc/intel/apollolake
+	# Override USB2 PER PORT register (PORT 4)
+	register "usb2eye[4]" = "{
+		.Usb20OverrideEn = 1,
+		.Usb20PerPortPeTxiSet = 7,
+		.Usb20PerPortTxiSet = 3,
+		.Usb20IUsbTxEmphasisEn = 3,
+		.Usb20PerPortTxPeHalf = 0,
+	}"
+
+	# Override USB2 PER PORT register (PORT 6)
+	register "usb2eye[6]" = "{
+		.Usb20OverrideEn = 1,
+		.Usb20PerPortPeTxiSet = 3,
+		.Usb20PerPortTxiSet = 0,
+		.Usb20IUsbTxEmphasisEn = 3,
+		.Usb20PerPortTxPeHalf = 0,
+	}"
+
 	# Intel Common SoC Config
 	#+-------------------+---------------------------+
 	#| Field             |  Value                    |