mcry mode='basic' does not use ancillas

[ankprd]

Information

• 0.14.2:
• 3:
• Ubuntu:

What is the current behavior?

The mcry gate (implemented in https://github.com/Qiskit/qiskit-terra/blob/master/qiskit/circuit/library/standard_gates/multi_control_rotation_gates.py) has a 'basic' mode that expects ancillas, but calls mct in its default 'noancilla' mode. (so both mcry(mode = 'noancilla') and mcry(mode='basic') use no ancillas and a lot of gates).

Steps to reproduce the problem

What is the expected behavior?

mcry in mode='basic' should call mct with mode='basic'

Suggested solutions