sparc/time: Add missing __init to init_tick_ops()

sparc/time: Add missing __init to init_tick_ops()

Code that was added to force gcc not to inline any function that isn't
explicitly declared as inline uncovered that init_tick_ops() isn't
marked as "__init". It is only called by __init functions and more
importantly it too calls an __init function which would require it to be
__init as well.

Link: http://lkml.kernel.org/r/201806060444.hdHcKOBy%fengguang.wu@intel.com
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: David S. Miller <davem@davemloft.net>