Add new symbolic names for revision ids, and convert KBL revids to use
them via the new stepping check macros.

This also fixes theoretical out of bounds access to kbl_revids array.

v3: upgrade dbg to warn on unknown revid (José)

v2: Rename stepping->step
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/79b6c48211c6b214165391d350d556bad748f747.1616764798.git.jani.nikula@intel.com