iwlwifi: move OTP defines

Since the PCI core shouldn't include the
iwl-eeprom.h header file, move the OTP
definitions into iwl-agn-hw.h which can
be included.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>