Fix a line trim to use the correct offset

We were previously trimming the string with the wrong prefix, which
meant that querying the Cpu brand from /proc/cpuinfo could be wrong if
the string matched "Processor\t: ".  We would use "model name\t: "
length to trim instead of the correct "Processor\t: " length.

BUG=788934

Change-Id: I1cc99e6c64ca89b25f53c51624db40cdafe24a6b
Reviewed-on: https://chromium-review.googlesource.com/791998
Reviewed-by: Tommy Nyquist <[email protected]>
Reviewed-by: Lei Zhang <[email protected]>
Commit-Queue: David Trainor <[email protected]>
Cr-Commit-Position: refs/heads/master@{#519802}
1 file changed