flash/nor/stm32h7x: use of wait queue flag instead of the busy flag

flash/nor/stm32h7x: use of wait queue flag instead of the busy flag

Based on RM0433.rev5 > Section 3.3.9 : Flash program operations:
  QW1/2: this bit indicates that a write, erase or option byte change
  operation is pending in the write queue or command queue buffer.
  It remains high until the write operation is complete.
  It supersedes the BSY1/2 status bit.

On this basis, stm32x_wait_status_busy is renamed accordingly to be
  'stm32x_wait_flash_op_queue'

Note : In this commit there is a fix of SR_ERROR_MASK value in flash loader algo
Note : This modification is mandatory for revision X, and backward compatible
  with old revisions

Change-Id: I59d2973317d76b01fbb0fb5e4a472a47d0a7a5b5
Signed-off-by: Laurent LEMELE <laurent.lemele@st.com>
Signed-off-by: Tarek BOCHKATI <tarek.bouchkati@gmail.com>
Reviewed-on: http://openocd.zylin.com/4883
Tested-by: jenkins
Reviewed-by: Christopher Head <chead@zaber.com>
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>