PRESUBMIT: Exclude some files from 80-character limit check.
PRESUBMIT: Exclude some files from 80-character limit check.

Exclude the following files from 80-characters line limit check:
* DEPS
* GN files (.gn and .gni)
* GYP files (.gyp and .gypi)

BUG=webrtc:4794
TESTED=Ran the presubmit check with a modified DEPS and GYP file before this change and verified it failed. Re-ran after these changes and verified it passed. I also tested editing a .cc file to be >80 chars and verified the check found it.
R=andrew@webrtc.org, sergiyb@chromium.org

Review URL: https://codereview.webrtc.org/1323943012 .

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#9877}

TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc