sh: Fix up tracepoint build fallout from static key introduction.

With the introduction of static keys, anything using tracepoints blows up
in the following manner:

include/trace/events/oom.h:8:13: error: initializer element is not constant
include/trace/events/oom.h:8:13: error: (near initialization for '__tracepoint_oom_score_adj_update')
include/trace/events/oom.h:8:13: error: initializer element is not constant
include/trace/events/oom.h:8:13: error: (near initialization for '__tracepoint_oom_score_adj_update.key')

This is a result of the STATIC_KEY_INIT_xxx defs wrapping ATOMIC_INIT()
which on sh includes an atomic_t typecast. Given that we don't really
need the typecast for anything anymore, the simplest solution is simply
to kill off the cast.

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>