mb/razer/blade_stealth_kbl: add panel_cfg

mb/razer/blade_stealth_kbl: add panel_cfg

This commit defines the panel_cfg register for the Razer Blade Stealth
(Kaby Lake). This enables libgfxinit support. These values are derived
from the stock firmware. First, VBIOSes were extracted from the stock
firmware. Then, intelvbtool was used to extract the VBT from each of the
VBIOS tables. Finally, intel_vbt_decode from igt-gpu-tools was used to
extract the register values. Although there were multiple VBIOSes
present in the firmware, all VBIOSes across both firmwares (on version
1.50 for the H2U and 8.02 for the H3Q) had the same register values.

Change-Id: I4c8b26ffb7a70d08655986084a714206d9d0c96a
Signed-off-by: Reagan Bohan <xbjfk.github@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82458
Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>