Diagonal copy support

All data descriptor for temporary copies of the diagonal to release dependencies on lower/upper parts should be moved to the driver level to avoid synchronization steps when possible. This is already done in the new HQR kernels but should be done in:

• pzgelqf.c
• pzgelqfrh.c
• pzgeqrf.c
• pzgeqrfrh.c
• pzhetrd_he2hb.c
• pztpgqrt.c
• pzunglq.c
• pzunglqrh.c
• pzungqr.c
• pzungqrrh.c
• pzunmlq.c
• pzunmlqrh.c
• pzunmqr.c
• pzunmqrrh.c