lib: dhry: remove unneeded <linux/mutex.h>

lib: dhry: remove unneeded <linux/mutex.h>

Patch series "lib: dhry: miscellaneous cleanups".

This patch series contains a few miscellaneous cleanups for the
Dhrystone benchmark test.

This patch (of 3):

The Dhrystone benchmark test does not use mutexes.

Link: https://lkml.kernel.org/r/cover.1705934853.git.geert+renesas@glider.be
Link: https://lkml.kernel.org/r/cf8fafaedccf96143f1513745c43a457480bfc24.1705934853.git.geert+renesas@glider.be
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>