Remove the macro get_personality

Remove the macro get_personality, use ->personality instead.

Cc: Christoph Hellwig <hch@infradead.org
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>