remoteproc: fix rproc_da_to_va in case of unallocated carveout

With introduction of rproc_alloc_registered_carveouts() which
delays carveout allocation just before the start of the remote
processor, rproc_da_to_va() could be called before all carveouts
are allocated.
This patch adds a check in rproc_da_to_va() to return NULL if
carveout is not allocated.

Fixes: d7c51706d095 ("remoteproc: add alloc ops in rproc_mem_entry struct")

Signed-off-by: Loic Pallardy <loic.pallardy@st.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index a97c4b7..dfa2f6e 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -207,6 +207,10 @@
 	list_for_each_entry(carveout, &rproc->carveouts, node) {
 		int offset = da - carveout->da;
 
+		/*  Verify that carveout is allocated */
+		if (!carveout->va)
+			continue;
+
 		/* try next carveout if da is too small */
 		if (offset < 0)
 			continue;