wl1251: Remove unused wl1251_acx_rate_policies

wl1251_acx_rate_policies() was added in 2009 by
commit 0e71bb08 ("wl1251: remove wl1251_ops")
but hasn't been used.

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://patch.msgid.link/20250622172804.116396-2-linux@treblig.org


Signed-off-by: Johannes Berg <johannes.berg@intel.com>