staging: r8188eu: Remove dead code

There are a few lines in this driver that depend on a macro
CONFIG_BT_COEXIST. But there's no Kconfig symbol of that name nor is
there a preprocessor define for that string. So remove these lines.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>