MIPS: Fix PKMAP with 32-bit MIPS huge page support

When 32-bit MIPS huge page support is enabled, we halve the number of
pointers a PTE page holds, making its last half go to waste.
Correspondingly, we should halve the number of kmap entries, as we just
initialized only a single pte table for that in pagetable_init().

Fixes: 3547631 ("MIPS: Add partial 32-bit huge page support")
Signed-off-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Author: stkid

arch/mips/include/asm/highmem.h

@@ -36,7 +36,7 @@ extern pte_t *pkmap_page_table;
  * easily, subsequent pte tables have to be allocated in one physical
  * chunk of RAM.
  */
-#ifdef CONFIG_PHYS_ADDR_T_64BIT
+#if defined(CONFIG_PHYS_ADDR_T_64BIT) || defined(CONFIG_MIPS_HUGE_TLB_SUPPORT)
 #define LAST_PKMAP 512
 #else
 #define LAST_PKMAP 1024