x86: hw_breakpoint.c arch_check_va_in_kernelspace and hw_breakpoint_handler should be static

arch_check_va_in_kernelspace() and hw_breakpoint_handler() is used only by same file so it should be static.

Also fixed non-ANSI function declaration of function 'arch_uninstall_thread_hw_breakpoint'

Fixed following sparse warnings :
  arch/x86/kernel/hw_breakpoint.c:124:42: warning: non-ANSI function declaration of function 'arch_uninstall_thread_hw_breakpoint'
  arch/x86/kernel/hw_breakpoint.c:169:5: warning: symbol 'arch_check_va_in_kernelspace' was not declared. Should it be static?
  arch/x86/kernel/hw_breakpoint.c:313:15: warning: symbol 'hw_breakpoint_handler' was not declared. Should it be static?

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: "K.Prasad" <prasad@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1245230059.2662.4.camel@ht.satnam>
Signed-off-by: Ingo Molnar <mingo@elte.hu>