chromium: Merge all FILES_${pn} assignments.
chromium: Merge all FILES_${pn} assignments.

And have one per line. It's easier to follow than one assignment followed by
multiple +='s.

Signed-off-by: Raphael Kubo da Costa <5fe4d20cf6ab8a2cf4e5e71d4c2d58346e96df0d@intel.com>

OSSystems/meta-browser,kraj/meta-browser,webdino/meta-browser,shr-distribution/meta-browser,schnitzeltony/meta-browser,twoerner/meta-browser,kraj/meta-browser,OSSystems/meta-browser,schnitzeltony/meta-browser,twoerner/meta-browser,webdino/meta-browser,twoerner/meta-browser,shr-distribution/meta-browser,OSSystems/meta-browser,webdino/meta-browser,kraj/meta-browser,webdino/meta-browser,twoerner/meta-browser,webdino/meta-browser,kraj/meta-browser,schnitzeltony/meta-browser,schnitzeltony/meta-browser,shr-distribution/meta-browser,shr-distribution/meta-browser,OSSystems/meta-browser