iwlwifi: mvm: Fix a memory leak in an error handling path in 'iwl_mvm_sar_get_wgds_table()'

We should free 'wgds.pointer' here as done a few lines above in another
error handling path.
It was allocated within 'acpi_evaluate_object()'.

Fixes: c52030a01ccc ("iwlwifi: mvm: add GEO_TX_POWER_LIMIT cmd for geographic tx power table")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>