CHROMIUM: spi: mtk-nor: Fix clock selection

The mtk-nor-spi controller is based on SPI, which
is initialized before nor. This initialization failed,
due to the selection of the first clock, which wasn't
labeled "spi" This resulted in a failed mtk-nor-spi probe on
Corsola boards.

BUG=b:396521623, b:396607629
TEST=emerge-{corsola-kernelnext\rauru} chromeos-kernel-6_6 \
      update_kernel && check if mtd devices are present &&
      run `futility gbb --get --flags --flash` with success.
UPSTREAM-TASK=b:379034916

Change-Id: I8bba4d5b80899da95c0c2e3daeaa5aa8ddf95727
Signed-off-by: Albert Jakieła <jakiela@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/6269778


Commit-Queue: Wojciech Macek <wmacek@google.com>
Reviewed-by: Fei Shao <fshao@chromium.org>
Reviewed-by: Wojciech Macek <wmacek@google.com>
Tested-by: Wojciech Macek <wmacek@google.com>
Signed-off-by: Hubert Mazur <hmazur@google.com>