iwlwifi: add csr configuration for 6300 devices

Recently we have switched the csr addresses and values configuration
from a single configuration to all devices to a per-device configuration.
Doing that, the configuration for 6300 devices wasn't set.
This missing definition introduced a kernel panic once trying to access
the csr's.

Add the missing 6300 csr configuration.

While at it, add a checker that the csr values were indeed
configured, and bail out more gracefully if not.

Fixes: a8cbb46f83 ("iwlwifi: allow different csr flags for different device families")
Signed-off-by: Golan Ben Ami <golan.ben.ami@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/cfg/6000.c

@@ -373,6 +373,7 @@ const struct iwl_cfg iwl6000_3agn_cfg = {
 	.eeprom_params = &iwl6000_eeprom_params,
 	.ht_params = &iwl6000_ht_params,
 	.led_mode = IWL_LED_BLINK,
+	.csr = &iwl_csr_v1,
 };
 
 MODULE_FIRMWARE(IWL6000_MODULE_FIRMWARE(IWL6000_UCODE_API_MAX));