drm/i915/dsi: unify naming and simplify checks for dphy params

drm/i915/dsi: unify naming and simplify checks for dphy params

Unify the naming of the data and clock lane timing parameters, and
simplify their bounds checks. Drop the debug messages on out of bounds
parameters as excessive.

Clarify the comment while at it.

Cc: William Tseng <william.tseng@intel.com>
Reviewed-by: William Tseng <william.tseng@intel.com>
Tested-by: William Tseng <william.tseng@intel.com>
Link: https://lore.kernel.org/r/d1a75ae7b9d93a0b50976b5de45ba2ca798991ad.1743682608.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>