PM: sleep: Replace snprintf() with scnprintf() in show_trace_dev_match()

PM: sleep: Replace snprintf() with scnprintf() in show_trace_dev_match()

Replace snprintf() with scnprintf() in show_trace_dev_match() to simplify
buffer length handling. The scnprintf() function returns the number of
characters actually written (excluding the null terminator), which
eliminates the need for manual length checking and clamping.

This change removes the redundant size check since scnprintf() guarantees
that the return value will never exceed the buffer size, making the code
cleaner and less error-prone.

Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
Link: https://patch.msgid.link/20250922055231.3523680-1-kaushlendra.kumar@intel.com
[ rjw: Subject adjustment ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>