rk35xx-vendor: build DRM_PANEL_MIPI_DBI as builtin

[amazingfate]

This driver will request firmware by the first compatiable string from devicetree, which is usually a device specific string not in the driver code. If this driver is built as module, it can't get loaded because only the first compatible string is used to probe driver. There is no such issue if this driver is built in kernel.

Description

ChatGPT has told me why:

Summary of Why It Works When Built-In

Device Tree Matching Is Explicit:

• Built-in drivers use the Device Tree's compatible property directly, bypassing the modalias mechanism.

Driver Probing During Boot:

• Built-in drivers are probed during boot for any matching devices, without relying on dynamic module loading.

modalias Irrelevance for Built-In Drivers:

• The modalias is only used to locate and load a module. When the driver is built into the kernel, it doesn't need to be located or loaded.

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also note any relevant details for your test configuration.

• Tested with arch: arm64: dts: add overlay for 240x135 lcd on hinlink-h88k linux-rockchip#311

Checklist:

Please delete options that are not relevant.

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules