riscv/mm: fix build error while PAGE_TABLE_CHECK enabled without MMU

mm/page_table_check.c: In function `__page_table_check_pte_clear':
mm/page_table_check.c:148:6: error: implicit declaration of function `pte_user_accessible_page'; did you mean `user_access_save'? [-Werror=implicit-function-declaration]
  if (pte_user_accessible_page(pte)) {
      ^~~~~~~~~~~~~~~~~~~~~~~~
      user_access_save

ARCH_SUPPORTS_PAGE_TABLE_CHECK should only enabled with MMU.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 3fee229 ("riscv/mm: enable ARCH_SUPPORTS_PAGE_TABLE_CHECK")
Signed-off-by: YueHaibing <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Pasha Tatashin <[email protected]>
Cc: Tong Tiangen <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: YueHaibing

arch/riscv/Kconfig

@@ -38,7 +38,7 @@ config RISCV
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU
 	select ARCH_SUPPORTS_HUGETLBFS if MMU
-	select ARCH_SUPPORTS_PAGE_TABLE_CHECK
+	select ARCH_SUPPORTS_PAGE_TABLE_CHECK if MMU
 	select ARCH_USE_MEMTEST
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU