qcacld-3.0: Re-remove IpaConfig from struct hdd_config
Previously change I5bea63b83ddac62504ef38019aa4034c4e18bca7
("qcacld-3.0: Add IPA CFG items and APIs") relocated the IPA
configuration from HDD to the IPA component. As part of that change
the IpaConfig field was removed from struct hdd_config.
Subsequently change I8cd30439d7ac3de7b550aa5042353cf30e04cbda
("qcacld-3.0: Refactor MLME CFG items and APIs for VHT") inexplicably
restored that field. Since that field is obsolete, remove it again.
In addition remove field IpaClkScalingEnable since this field has
never been used by the current version of the driver.
Change-Id: Ic08dc4b1ec82848512e7667c870dc18de1a343be
CRs-Fixed: 2367389