drm/i915/bios: Rename find_section to find_bdb_section

This prevents a namespace collision on other archs.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230315121924.2314693-1-jani.nikula@intel.com