Remove driver entry points for {get|set}_max_ops().

Move the global variable to the PSA layer, and just set that when calling PSA
level functions.

Move the internal ecp set to before each ecp call.

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index 80bf5c9..48c45df 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -4217,6 +4217,9 @@
  *                              \c psa_sign_hash_interruptible_abort() on
  *                              the operation, a value of 0 will be returned.
  *
+ * \note                        This interface is guaranteed re-entrant and
+ *                              thus may be called from driver code.
+ *
  * \warning                     This is a beta API, and thus subject to change
  *                              at any point. It is not bound by the usual
  *                              interface stability promises.