[otp_ctrl, doc] Explicit integrity/consistency check write order

In the otp_ctrl an integrity/consistency check is triggered as soon as
either the `INTEGRITY_CHECK_PERIOD` or `CONSISTENCY_CHECK_PERIOD`
registers are written. The following check, depending on the number of
instantiated partitions, may last for hundreds of cycles. Writing a
value into the `CHECK_TIMEOUT` register while the checks are still
ongoing will trigger an unnecessary timeout error that transfers the
otp_ctlr into an error state.

This commit adjusts the documentation to make it clear that the
`CHECK_TIMEOUT` register should be written before
`INTEGRITY_CHECK_PERIOD` and `CONSISTENCY_CHECK_PERIOD`. Following the
Programmer's Guide verbatim before may lead to implementations that
trigger this unintended error condition.

Signed-off-by: Andrea Caforio <[email protected]>
(cherry picked from commit ebaf6b7)

Author: andrea-caforio

Diff for: hw/ip/otp_ctrl/doc/programmers_guide.md

@@ -15,8 +15,9 @@ The only initialization steps that SW should perform are:
 
 1. Check that the OTP controller has successfully initialized by reading [`STATUS`](registers.md#status). I.e., make sure that none of the ERROR bits are set, and that the DAI is idle ([`STATUS.DAI_IDLE`](registers.md#status)).
 2. Set up the periodic background checks:
-    - Choose whether to enable periodic [background checks](#partition-checks) by programming nonzero mask values to [`INTEGRITY_CHECK_PERIOD`](registers.md#integrity_check_period) and [`CONSISTENCY_CHECK_PERIOD`](registers.md#consistency_check_period).
-    - Choose whether such checks shall be subject to a timeout by programming a nonzero timeout cycle count to [`CHECK_TIMEOUT`](registers.md#check_timeout).
+    - Choose whether the periodic [background checks](#partition-checks) shall be subject to a timeout by programming a nonzero timeout cycle count to [`CHECK_TIMEOUT`](registers.md#check_timeout).
+      In this case, the [`CHECK_TIMEOUT`](registers.md#check_timeout) register must be set before the [`INTEGRITY_CHECK_PERIOD`](registers.md#integrity_check_period) and [`CONSISTENCY_CHECK_PERIOD`](registers.md#consistency_check_period) registers (see next point).
+    - Enable periodic [background checks](#partition-checks) by programming nonzero mask values to [`INTEGRITY_CHECK_PERIOD`](registers.md#integrity_check_period) and [`CONSISTENCY_CHECK_PERIOD`](registers.md#consistency_check_period).
     - It is recommended to lock down the background check registers via [`CHECK_REGWEN`](registers.md#check_regwen), once the background checks have been set up.
 
 If needed, one-off integrity and consistency checks can be triggered via [`CHECK_TRIGGER`](registers.md#check_trigger).