net/tls: build_protos moved to common routine

build protos is required for tls_hw_prot also hence moved to
'tls_build_proto' and called as required from tls_init
and tls_hw_proto. This is required since build_protos
for v4 is moved from tls_register to tls_init in
commit <28cb6f1e>

Signed-off-by: Atul Gupta <atul.gupta@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>