Ozone: Remove the use_wayland_egl build flag

This flag is always enabled by default. It was introduced to allow
building the Wayland Ozone platform without the egl packages but these
were added to the sysroot in
https://codereview.chromium.org/2415933004
so that should no longer be a problem.

BUG=None

Review-Url: https://chromiumcodereview.appspot.com/2431383002
Cr-Commit-Position: refs/heads/master@{#426414}
2 files changed