[PATCH 05/16] printk: implement log_seq_range() and ext_log_from_seq()

Implement two functions to access log messages by their sequence numbers. * log_seq_range() determines the currently available sequence number range. * ext_log_from_seq() outputs log message identified by a given sequence number in the extended format. These will be used to implement

[PATCH 05/16] printk: implement log_seq_range() and ext_log_from_seq()

Implement two functions to access log messages by their sequence numbers. * log_seq_range() determines the currently available sequence number range. * ext_log_from_seq() outputs log message identified by a given sequence number in the extended format. These will be used to implement