iwlwifi: remove unnecessary apmg settings

This patch remove settings of APMG_PS_CTRL_VAL_RESET_REQ
from 4965 this should be used only for 3945

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>