wil6210: add 'info' debugfs entry

Use 'info' debugfs entry for misc. assorted information.
Start with indication whether platform is AC-powered;
will use it later for power related decisions

Change-Id: I58d2f55ab5f7ef84f5a92609ffa12031d8a9a91f
Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Git-commit: 84bb29b7ab71daed9318073dd33632274373a1ea
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-testing.git


Signed-off-by: Hamad Kadmany <hkadmany@codeaurora.org>