x86: mm/pageattr.c declare arch_report_meminfo before they get used

declared arch_report_meminfo() in asm-x86/pgtable.h as it will be also accessible by fs/proc/proc_misc.c
Signed-off-by: Jaswinder Singh <jaswinder@infradead.org>

include/asm-x86/pgtable.h

@@ -310,6 +310,8 @@ static inline void native_pagetable_setup_start(pgd_t *base) {}
 static inline void native_pagetable_setup_done(pgd_t *base) {}
 #endif
 
+extern int arch_report_meminfo(char *page);
+
 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>
 #else  /* !CONFIG_PARAVIRT */