samples:philosophers:Reformated 80-column width, 80-chars tabs

This patch reformats philosophers sample to fit in 80 columns
with 8-char tabs. It also fixes other coding style issues
reported by chechpatch.pl script with -f option.

Change-Id: Ie7ed59db4e67e279a26000247a1838221ac37cd3
Signed-off-by: Yannis Damigos <giannis.damigos@gmail.com>