qcacmn: Fix function declaration warning

Fixes the following warnings/errors with clang 15:

../drivers/staging/wlan-qc/qcacld-3.0/../qca-wifi-host-cmn/target_if/core/src/target_if_main.c:91:40: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
struct target_if_ctx *target_if_get_ctx()
                                       ^
                                        void
../drivers/staging/wlan-qc/qcacld-3.0/../qca-wifi-host-cmn/hif/src/ce/ce_service_legacy.c:1320:34: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
struct ce_ops *ce_services_legacy()
                                 ^
                                  void

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Change-Id: I551ba9f0a641b1f3c7149e680816d25f5ae91074