iwlwifi: fix malformed CONFIG_IWLWIFI_PCIE_RTPM default

'default false' should be 'default n', though they happen to have the
same effect here, due to undefined symbols ('false' in this case)
evaluating to n in a tristate sense.

Remove the default instead of changing it. bool and tristate symbols
implicitly default to n.

Discovered with the
https://github.com/ulfalizer/Kconfiglib/blob/master/examples/list_undefined.py
script.
Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/Kconfig

@@ -91,7 +91,6 @@ config IWLWIFI_BCAST_FILTERING
 config IWLWIFI_PCIE_RTPM
        bool "Enable runtime power management mode for PCIe devices"
        depends on IWLMVM && PM && EXPERT
-       default false
        help
          Say Y here to enable runtime power management for PCIe
          devices.  If enabled, the device will go into low power mode