Shorten certificate parsing code a little.

Comparing data is a much easier idiom than CBS_skip + a CBS_len check.

Change-Id: I3efe925734c76f3494cad682445291ae83750a7e
Reviewed-on: https://boringssl-review.googlesource.com/2500
Reviewed-by: Adam Langley <agl@google.com>
2 files changed