flash: Rename write_flash to flash_write

Change-Id: I4b41aac597299c93369d8998b03a7d3e2a128742
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/vpnor/test/write_prsv.cpp b/vpnor/test/write_prsv.cpp
index b89b954..c358ae1 100644
--- a/vpnor/test/write_prsv.cpp
+++ b/vpnor/test/write_prsv.cpp
@@ -45,7 +45,7 @@
 
     /* Test */
     memset(src, 0xaa, sizeof(src));
-    rc = write_flash(ctx, 0x1000, src, sizeof(src));
+    rc = flash_write(ctx, 0x1000, src, sizeof(src));
     assert(rc == 0);
 
     /* Verify */