EDAC/skx_common: Swap memory controller index mapping

EDAC/skx_common: Swap memory controller index mapping

The current mapping of memory controller indices is from physical index [1]
to logical index [2], as show below:

  skx_dev->imc[pmc].mc_mapping = lmc

Since skx_dev->imc[] is an array of present memory controller instances,
mapping memory controller indices from logical index to physical index,
as show below, is more reasonable. This is also a preparatory step for
making skx_dev->imc[] a flexible array.

  skx_dev->imc[lmc].mc_mapping = pmc

Both mappings are equivalent. No functional changes intended.

[1] Indices for memory controllers include both those present to the
    OS and those disabled by BIOS.

[2] Indices for memory controllers present to the OS.

Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/20250731145534.2759334-4-qiuxu.zhuo@intel.com