remtoteproc: maintain max notifyid

Some of the rproc drivers (STE modem specifically) needs to know
the range of the notification IDs used for notifying the device.

Maintain a variable in struct rproc holding the largest allocated
notification id, so low-level rproc drivers could access it.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
[ohad: rebase, slightly edit commit log]
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
index 2ccc3fe..faf3332 100644
--- a/include/linux/remoteproc.h
+++ b/include/linux/remoteproc.h
@@ -400,6 +400,7 @@
  * @crash_cnt: crash counter
  * @crash_comp: completion used to sync crash handler and the rproc reload
  * @recovery_disabled: flag that state if recovery was disabled
+ * @max_notifyid: largest allocated notify id.
  */
 struct rproc {
 	struct klist_node node;
@@ -427,6 +428,7 @@
 	unsigned crash_cnt;
 	struct completion crash_comp;
 	bool recovery_disabled;
+	int max_notifyid;
 };
 
 /* we currently support only two vrings per rvdev */