staging:rtl8192u: Refactor enum VERSION_819xU - Style

Rename enumerated type VERSION_819xU to version_819xu to clear
checkpatch issue with CamelCase naming. Additionally the constants
defined by the type are renamed for the same reason.

Remove the 'typedef' directive to clear the checkpatch issue with
defining new types.

The enumerated type has been moved to the file where the type is
actually used, r8192U.h

Additionally the memeber variable, which uses the type
(card_8192_version), has been changed to use the type to enable
compiler typechecking.

These are coding style changes which should not impact runtime code
execution.

Signed-off-by: John Whitmore <johnfwhitmore@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>