drm/i915/lnl: Fix check for TC phy

With MTL adding PICA between the port and the real phy, the path
add for DG2 stopped being followed and newer platforms are simply using
the older path for TC phys. LNL is no different than MTL in this aspect,
so just add it to the mess. In future the phy and port designation and
deciding if it's TC should better be cleaned up.

To make it just a bit better, also change intel_phy_is_snps() to show
this is DG2-only.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231026184045.1015655-3-lucas.demarchi@intel.com