drivers/gpu/drm/bridge/samsung-dsim.c link error

[Aleksandr Nogikh <nogikh@google.com>]

Hello,

We've been seing the following linker error on arm64 syzbot instances:

ld.lld: error: undefined symbol: phy_mipi_dphy_get_default_config_for_hsclk
>>> referenced by samsung-dsim.c:731 (drivers/gpu/drm/bridge/samsung-dsim.c:731)
>>>               drivers/gpu/drm/bridge/samsung-dsim.o:(samsung_dsim_init) in archive vmlinux.a

Steps to reproduce on the latest linux-next:

$ git checkout next-20230803
$ wget -O '.config' 'https://raw.githubusercontent.com/google/syzkaller/master/dashboard/config/linux/upstream-arm64-kasan.config'
$ make CC=clang ARCH=arm64 LD=ld.lld CROSS_COMPILE=aarch64-linux-gnu- olddefconfig

This also prints:

WARNING: unmet direct dependencies detected for GENERIC_PHY_MIPI_DPHY
  Depends on [n]: GENERIC_PHY [=n]
  Selected by [y]:
  - DRM_NWL_MIPI_DSI [=y] && DRM_BRIDGE [=y] && DRM [=y] && COMMON_CLK [=y] && OF [=y] && HAS_IOMEM [=y]
  - DRM_SAMSUNG_DSIM [=y] && DRM [=y] && DRM_BRIDGE [=y] && COMMON_CLK [=y] && OF [=y] && HAS_IOMEM [=y]

$ make CC=clang ARCH=arm64 LD=ld.lld CROSS_COMPILE=aarch64-linux-gnu- -j$(nproc)

The kernel should have still compiled fine even despite the message above, right?

Could you please take a look?

-- 
Thank you!
Aleksandr