ARM: spear: Do not use timer namespace for timer_shutdown() function

A new "shutdown" timer state is being added to the generic timer code. One
of the functions to change the timer into the state is called
"timer_shutdown()". This means that there can not be other functions called
"timer_shutdown()" as the timer code owns the "timer_*" name space.

Rename timer_shutdown() to spear_timer_shutdown() to avoid this conflict.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lkml.kernel.org/r/20221106212701.822440504@goodmis.org
Link: https://lore.kernel.org/all/20221105060155.228348078@goodmis.org/
Link: https://lore.kernel.org/r/20221110064146.810953418@goodmis.org
Link: https://lore.kernel.org/r/20221123201624.513863211@linutronix.de