crypto: qat - fix initialization of pfvf cap_msg structures

Initialize fully the structures cap_msg containing the device
capabilities from the host.

This is to fix the following warning when compiling the QAT driver
using the clang compiler with CC=clang W=2:

    drivers/crypto/qat/qat_common/adf_pfvf_vf_msg.c:99:44: warning: missing field 'ext_dc_caps' initializer [-Wmissing-field-initializers]
            struct capabilities_v3 cap_msg = { { 0 }, };
                                                      ^

Fixes: 851ed498

 ("crypto: qat - exchange device capabilities over PFVF")
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>