mm/rmap: remove unneeded semicolon in page_not_mapped()

stable inclusion
from linux-4.19.197
commit 784445344c9e7cdef2a2a724fab34243933a91dc

--------------------------------

[ Upstream commit e0af87ff ]

Remove extra semicolon without any functional change intended.

Link: https://lkml.kernel.org/r/20210127093425.39640-1-linmiaohe@huawei.com


Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>