[POWERPC] Remove a couple of unused definitions from pgtable_32.c

In arch/powerpc/mm/pgtable_32.c, the variable io_bat_index and the
macro is_power_of_4() no longer have any users. This removes them.

Signed-off-by: David Gibson <[e-mail]>
Signed-off-by: Paul Mackerras <[e-mail]>

arch/powerpc/mm/pgtable_32.c

···
 unsigned long ioremap_base;
 unsigned long ioremap_bot;
 EXPORT_SYMBOL(ioremap_bot);	/* aka VMALLOC_END */
-int io_bat_index;
 
 #if defined(CONFIG_6xx) || defined(CONFIG_POWER3)
 #define HAVE_BATS	1
···
 		p += PAGE_SIZE;
 	}
 }
-
-/* is x a power of 4? */
-#define is_power_of_4(x)	is_power_of_2(x) && (ffs(x) & 1)
 
 /* Scan the real Linux page tables and return a PTE pointer for
  * a virtual address in a context.