ice: Fix clang -Wimplicit-fallthrough in ice_pull_qvec_from_rc()

Clang warns:

drivers/net/ethernet/intel/ice/ice_lib.c:1906:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
        default:
        ^
drivers/net/ethernet/intel/ice/ice_lib.c:1906:2: note: insert 'break;' to avoid fall-through
        default:
        ^
        break;
1 error generated.

Clang is a little more pedantic than GCC, which does not warn when
falling through to a case that is just break or return. Clang's version
is more in line with the kernel's own stance in deprecated.rst, which
states that all switch/case blocks must end in either break,
fallthrough, continue, goto, or return. Add the missing break to silence
the warning.

Link: https://github.com/ClangBuiltLinux/linux/issues/1482
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/ice/ice_lib.c

@@ -1983,6 +1983,7 @@ static struct ice_q_vector *ice_pull_qvec_from_rc(struct ice_ring_container *rc)
 	case ICE_TX_CONTAINER:
 		if (rc->tx_ring)
 			return rc->tx_ring->q_vector;
+		break;
 	default:
 		break;
 	}