camera: Add kSessionDataKeyEisFrameDelayIntPtr in session data

Bug: 162715137
Test: GCA, CTS, ITS
Change-Id: I5348f68f72e28bf7618eaf06f2f245f58877b27d
(cherry picked from commit 417d4d148904dd3d865ea6ff439f2d0f43e45294)
diff --git a/common/hal/common/session_data_defs.h b/common/hal/common/session_data_defs.h
index 9510583..0adcbc2 100644
--- a/common/hal/common/session_data_defs.h
+++ b/common/hal/common/session_data_defs.h
@@ -42,6 +42,10 @@
 enum SessionDataKey : uint64_t {
   kSessionDataKeyInvalidKey = 0,
   // Add HAL-visible keys here (visible to GCH and HWL).
+  // A pointer to an int variable that indicates current
+  // Eis frame delay number.
+  // The pointer will be valid for the entire session.
+  kSessionDataKeyEisFrameDelayIntPtr,
   kSessionDataKeyBeginHwlKeys = 0xFFFFFFFF
 };