drm/i915/cnl: Fix LSPCON support.

drm/i915/cnl: Fix LSPCON support.

When LSPCON support was extended to CNL
one part was missed on lspcon_init.

So, instead of adding check per platform on lspcon_init
let's use HAS_LSPCON that is already there for that
purpose.

Fixes: ff15947e0f02 ("drm/i915/cnl: LSPCON support is gen9+")
Cc: Shashank Sharma <[email protected]>
Cc: Paulo Zanoni <[email protected]>
Signed-off-by: Rodrigo Vivi <[email protected]>
Reviewed-by: Jani Nikula <[email protected]>
Reviewed-by: Shashank Sharma <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]