x86: clean up declarations and variables

Impact: cleanup, no code changed

 - syscalls.h       update declarations due to unifications
 - irq.c            declare smp_generic_interrupt() before it gets used
 - process.c        declare sys_fork() and sys_vfork() before they get used
 - tsc.c            rename tsc_khz shadowed variable
 - apic/probe_32.c  declare apic_default before it gets used
 - apic/nmi.c       prev_nmi_count should be unsigned
 - apic/io_apic.c   declare smp_irq_move_cleanup_interrupt() before it gets used
 - mm/init.c        declare direct_gbpages and free_initrd_mem before they get used

Signed-off-by: Jaswinder Singh Rajput <jaswinder@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/pgtable_64.h

@@ -25,10 +25,6 @@ extern pgd_t init_level4_pgt[];
 
 extern void paging_init(void);
 
-#endif /* !__ASSEMBLY__ */
-
-#ifndef __ASSEMBLY__
-
 #define pte_ERROR(e)					\
 	printk("%s:%d: bad pte %p(%016lx).\n",		\
 	       __FILE__, __LINE__, &(e), pte_val(e))
@@ -135,8 +131,6 @@ static inline int pgd_large(pgd_t pgd) { return 0; }
 
 #define update_mmu_cache(vma, address, pte) do { } while (0)
 
-extern int direct_gbpages;
-
 /* Encode and de-code a swap entry */
 #if _PAGE_BIT_FILE < _PAGE_BIT_PROTNONE
 #define SWP_TYPE_BITS (_PAGE_BIT_FILE - _PAGE_BIT_PRESENT - 1)