wil6210: fix debugfs memory access alignment

All wil6210 device memory access should be 4 bytes aligned. In io
blob wil6210 did not force alignment for read function, this caused
alignment fault on some platforms.
Fixing that by accessing all 4 lower bytes and return to host the
requested data.

Signed-off-by: Ahmad Masri <amasri@codeaurora.org>
Signed-off-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>