kasan: fix coccinelle warnings in kasan_p*_table

kasan_p4d_table(), kasan_pmd_table() and kasan_pud_table() are declared
as returning bool, but return 0 instead of false, which produces a
coccinelle warning.  Fix it.

Link: http://lkml.kernel.org/r/1fa6fadf644859e8a6a8ecce258444b49be8c7ee.1551716733.git.andreyknvl@google.com
Fixes: 0207df4f ("kernel/memremap, kasan: make ZONE_DEVICE with work with KASAN")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: kbuild test robot <lkp@intel.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/kasan/init.c

@@ -42,7 +42,7 @@ static inline bool kasan_p4d_table(pgd_t pgd)
 #else
 static inline bool kasan_p4d_table(pgd_t pgd)
 {
-	return 0;
+	return false;
 }
 #endif
 #if CONFIG_PGTABLE_LEVELS > 3
@@ -54,7 +54,7 @@ static inline bool kasan_pud_table(p4d_t p4d)
 #else
 static inline bool kasan_pud_table(p4d_t p4d)
 {
-	return 0;
+	return false;
 }
 #endif
 #if CONFIG_PGTABLE_LEVELS > 2
@@ -66,7 +66,7 @@ static inline bool kasan_pmd_table(pud_t pud)
 #else
 static inline bool kasan_pmd_table(pud_t pud)
 {
-	return 0;
+	return false;
 }
 #endif
 pte_t kasan_early_shadow_pte[PTRS_PER_PTE] __page_aligned_bss;