onclite: Kill deprecated/unneeded board flags

* BLUETOOTH_HCI_USE_MCT - Deprecated.
* BOARD_USES_QCNE - Only referenced in very old BSPs.
* MAX_EGL_CACHE_KEY_SIZE - Not used anywhere.
* MAX_EGL_CACHE_SIZE - Not used anywhere.
* TARGET_KERNEL_ARCH - no-op unless it differs from TARGET_ARCH.
* WIFI_HIDL_FEATURE_DISABLE_AP_MAC_RANDOMIZATION - Deprecated

Change-Id: I8d140fecdbbaac979bc8398745ffa95b911e4c89