x86: convert permanent_kmaps_init() from macro to inline

Impact: cleanup

This compiler warning:

  arch/x86/mm/init_32.c:515: warning: unused variable 'pgd_base'

triggers because permanent_kmaps_init() is a CPP macro in the
!CONFIG_HIGHMEM case, that does not tell the compiler that the
'pgd_base' parameter is used.

Convert permanent_kmaps_init() (and set_highmem_pages_init()) to
C inline functions - which gives the parameter a proper type and
which gets rid of the compiler warning as well.
Signed-off-by: NIngo Brueckl <ib@wupperonline.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/mm/init_32.c

@@ -434,8 +434,12 @@ static void __init set_highmem_pages_init(void)
 #endif /* !CONFIG_NUMA */
 
 #else
-# define permanent_kmaps_init(pgd_base)		do { } while (0)
-# define set_highmem_pages_init()	do { } while (0)
+static inline void permanent_kmaps_init(pgd_t *pgd_base)
+{
+}
+static inline void set_highmem_pages_init(void)
+{
+}
 #endif /* CONFIG_HIGHMEM */
 
 void __init native_pagetable_setup_start(pgd_t *base)