Staging: rtl8192u: Remove unnecessary macro definition

This patch removes the IEEE80211_PRINT_STR macro definition because it appears
only in the header file and it doesn't serve any purpose in this context.

Signed-off-by: Cristina Opriceana <cristina.opriceana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>