kmsro: Extend to include hx8357d.

kmsro: Extend to include hx8357d.

This allows vc4 to initialize on the Adafruit PiTFT 3.5" touchscreen with
the hx8357d tinydrm driver

v2: Whitespace fix noted by Eric Engestrom, update commit message for the
    driver being merged.
v3: Rebase on Rob Herring's pipe-loader changes.

Acked-by: Eric Engestrom <eric.engestrom@intel.com> (v1)
Acked-by: Emil Velikov <emil.velikov@collabora.com> (v1)