mwifiex: fix typo in PCIe adapter NULL check

Add missing "!" as we are supposed to check "!card->adapter"
in PCIe suspend handler.

Cc: "3.2+" <stable@vger.kernel.org>
Signed-off-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Reviewed-by: Sergey V. <sftp.mtuci@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>