wlan: use correct base type for abstracted types

In order to provide OS abstraction the WLAN driver defines it own
8-bit, 16-bit, 32-bit, and 64-bit typedefs.  The underlying types
chosen are appropriate for ILP32 architecture, but they are not
appropriate for LP64 architecture.  Redefine the abstracted types so
that that are of the correct size irrespective of the underlying
architecture.

Change-Id: I5d491970daec047b312a4ab15ac1b892531b0916
CRs-fixed: 567110