drm/tinydrm: fix semicolon.cocci warnings

drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c:454:2-3: Unneeded semicolon

 Remove unneeded semicolon.

Generated by: scripts/coccinelle/misc/semicolon.cocci

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170223164647.GA2519@lkp-ws02