iwlwifi: mvm: remove the default calibration values for 7000

The fw is now able to run TX_IQ_SKEW and RX_IQ_SKEW by
itself. No need for default values any more.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Reviewed-by: Dor Shaish <dor.shaish@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>