[PATCH] blkparse: hardcode the default formats instead of parsing them

[PATCH] blkparse: hardcode the default formats instead of parsing them

It takes a lot of time to manually parse each individual trace,
and there's really no point in doing that work if the user did
not specificy a custom format. We now only parse the given custom
formats.

Without any custom formats (eg the default), parsing a trace of
1.3 million entries now takes 4.3 seconds where it took 11.25 before.