EDAC/{skx_common,i10nm}: Use scnprintf() for safer buffer handling

snprintf() is fragile when its return value will be used to append
additional data to a buffer. Use scnprintf() instead.

Signed-off-by: Wang Haoran <haoranwangsec@gmail.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Tested-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Link: https://lore.kernel.org/r/20250715131700.1092720-1-haoranwangsec@gmail.com