ring-buffer: Remove condition to add timestamp in fast path

There's a condition to check if we should add a time extend or
not in the fast path. But this condition is racey (in the sense
that we can add a unnecessary time extend, but nothing that
can break anything). We later check if the time or event time
delta should be zero or have real data in it (not racey), making
this first check redundant.

This check may help save space once in a while, but really is
not worth the hassle to try to save some space that happens at
most 134 ms at a time.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>