Staging: wlan-ng: Merge string literals on adjacent lines in prism2fw.c

This patch fixes the 'quoted string split across lines' checkpatch.pl
warning in prism2fw.c.

Signed-off-by: Artemiy Volkov <artemiyv@acm.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>