sparc/kernel/: possible cleanups

sparc/kernel/: possible cleanups

This patch contains the following possible cleanups:
- make the following needlessly global code static:
  - apc.c: apc_swift_idle()
  - ebus.c: ebus_blacklist_irq()
  - ebus.c: fill_ebus_child()
  - ebus.c: fill_ebus_device()
  - entry.S: syscall_is_too_hard
  - etra: tsetup_sun4c_stackchk
  - head.S: cputyp
  - head.S: prom_vector_p
  - idprom.c: Sun_Machines[]
  - ioport.c: _sparc_find_resource()
  - ioport.c: create_proc_read_entry()
  - irq.c: struct sparc_irq[]
  - rtrap.S: sun4c_rett_stackchk
  - setup.c: prom_sync_me()
  - setup.c: boot_flags
  - sun4c_irq.c: sun4c_sbint_to_irq()
  - sun4d_irq.c: sbus_tid[]
  - sun4d_irq.c: struct sbus_actions
  - sun4d_irq.c: sun4d_sbint_to_irq()
  - sun4m_irq.c: sun4m_sbint_to_irq()
  - sun4m_irq.c: sun4m_get_irqmask()
  - sun4m_irq.c: sun4m_timers
  - sun4m_smp.c: smp4m_cross_call()
  - sun4m_smp.c: smp4m_blackbox_id()
  - sun4m_smp.c: smp4m_blackbox_current()
  - time.c: sp_clock_typ
  - time.c: sbus_time_init()
  - traps.c: instruction_dump()
  - wof.S: spwin_sun4c_stackchk
  - wuf.S: sun4c_fwin_stackchk
- #if 0 the following unused code:
  - process.c: sparc_backtrace_lock
  - process.c: __show_backtrace()
  - process.c: show_backtrace()
  - process.c: smp_show_backtrace_all_cpus()
- remove the following unused code:
  - entry.S: __handle_exception
  - smp.c: smp_num_cpus
  - smp.c: smp_activated
  - smp.c: __cpu_number_map[]
  - smp.c: __cpu_logical_map[]
  - smp.c: bitops_spinlock
  - traps.c: trap_curbuf
  - traps.c: trapbuf[]
  - traps.c: linux_smp_still_initting
  - traps.c: thiscpus_tbr
  - traps.c: thiscpus_mid

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>