x86/mce/threshold: Remove the redundant this_cpu_dec_return()

x86/mce/threshold: Remove the redundant this_cpu_dec_return()

The 'storm' variable points to this_cpu_ptr(&storm_desc). Access the
'stormy_bank_count' field through the 'storm' to avoid calling
this_cpu_*() on the same per-CPU variable twice.

This minor optimization reduces the text size by 16 bytes.

  $ size threshold.o.*
     text	   data	    bss	    dec	    hex	filename
     1395	   1664	      0	   3059	    bf3	threshold.o.old
     1379	   1664	      0	   3043	    be3	threshold.o.new

No functional changes intended.

Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Link: https://lore.kernel.org/r/20241212140103.66964-3-qiuxu.zhuo@intel.com