drm/i915/dram: Fix ICL DIMM_S decoding

drm/i915/dram: Fix ICL DIMM_S decoding

Unfortunately the MAD_DIMM DIMM_S and DIMM_L bits on ICL are
not idential, so we are currently decoding DIMM_S incorrectly.

Fix the problem by defining the DIMM_S and DIMM_L bits separately.
And for consistency do that same for SKL, even though there the
bits do match between the two DIMMs. The result is rather
repetitive in places, but I didn't feel like obfuscatign things
with cpp macros/etc.

Broken decoding on Dell XPS 13 7390 2-in-1:
 CH0 DIMM L size: 32 Gb, width: X16, ranks: 2, 16Gb+ DIMMs: no
 CH0 DIMM S size: 32 Gb, width: X32, ranks: 3, 16Gb+ DIMMs: no
 CH0 ranks: 2, 16Gb+ DIMMs: no
 CH1 DIMM L size: 32 Gb, width: X16, ranks: 2, 16Gb+ DIMMs: no
 CH1 DIMM S size: 32 Gb, width: X32, ranks: 3, 16Gb+ DIMMs: no
 CH1 ranks: 2, 16Gb+ DIMMs: no
 Memory configuration is symmetric? no

Fixed decoding on Dell XPS 13 7390 2-in-1:
 CH0 DIMM L size: 32 Gb, width: X16, ranks: 2, 16Gb+ DIMMs: no
 CH0 DIMM S size: 32 Gb, width: X16, ranks: 2, 16Gb+ DIMMs: no
 CH0 ranks: 2, 16Gb+ DIMMs: no
 CH1 DIMM L size: 32 Gb, width: X16, ranks: 2, 16Gb+ DIMMs: no
 CH1 DIMM S size: 32 Gb, width: X16, ranks: 2, 16Gb+ DIMMs: no
 CH1 ranks: 2, 16Gb+ DIMMs: no
 Memory configuration is symmetric? yes

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20251029204215.12292-4-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>