rc80211_pid: Fix fast_start parameter handling

This removes the fast_start parameter from the rc_pid parameters
information and instead uses the parameter macro when initializing
the rc_pid state. Since the parameter is only used on initialization,
there is no point of making exporting it via debugfs. This also fixes
uninitialized memory references to the fast_start and norm_offset
parameters detected by the kmemcheck utility.  Thanks to Vegard Nossum
for reporting the bug.

Signed-off-by: Mattias Nissler <mattias.nissler@gmx.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>