drivers/net: wireless/ath/ath5k/debug.c does not need module.h

It only has module_param and EXPORT_SYMBOL, so now that export.h
is in scope at the same time as the recent ath5k update, we can
delete this module.h include.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>