staging:rtl8192u: Move HTSetConnectBwModeCallback() - Style

The function HTSetConnectBwModeCallback() is only used in the file
in which it is defined, so has been changed to being of type 'static'.

Additionally the function is defined after it is used so a prototype
was included in the file. This prototype, in the middle of the file
has been removed and the function implementation moved so that it is
defined before it is used in the file.

This is a coding style change which should have no impact on runtime
code execution.

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