Core: Remove the index member in runtime data structure

Remove the index member in runtime data structure to minimize
the memory usage. Refine the implementation of
tfm_spm_partition_get_privileged_mode by passing partition
flags instead of partition index.

Change-Id: I6d2bc92dccfb8fe79ca282e5648625ff6c780ef2
Signed-off-by: Summer Qin <summer.qin@arm.com>
diff --git a/secure_fw/spm/spm_api.h b/secure_fw/spm/spm_api.h
index aebcc5a..b9b344a 100644
--- a/secure_fw/spm/spm_api.h
+++ b/secure_fw/spm/spm_api.h
@@ -108,7 +108,6 @@
                                          * Service signal mask passed by
                                          * psa_wait()
                                          */
-    uint32_t index;                     /* Partition index */
 };
 
 #ifdef TFM_PSA_API
@@ -415,12 +414,12 @@
 /**
  * \brief                   Get the current partition mode.
  *
- * \param[in] partition_idx                 Index of current partition
+ * \param[in] partition_flags               Flags of current partition
  *
  * \retval TFM_PARTITION_PRIVILEGED_MODE    Privileged mode
  * \retval TFM_PARTITION_UNPRIVILEGED_MODE  Unprivileged mode
  */
-uint32_t tfm_spm_partition_get_privileged_mode(uint32_t partition_idx);
+uint32_t tfm_spm_partition_get_privileged_mode(uint32_t partition_flags);
 
 /******************** Service handle management functions ********************/