hw/omap_l4.c: Add helper function omap_l4_region_base

Add helper function omap_l4_region_base() to return the base address
of a particular region of an L4 target agent.

Signed-off-by: Juha Riihimäki <juha.riihimaki@nokia.com>
[Riku Voipio: Fixes and restructuring patchset]
Signed-off-by: Riku Voipio <riku.voipio@iki.fi>
[Peter Maydell: More fixes and cleanups for upstream submission]
Signed-off-by:  Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andrzej Zaborowski <andrew.zaborowski@intel.com>
diff --git a/hw/omap_l4.c b/hw/omap_l4.c
index 4af0ca8..59c84b1 100644
--- a/hw/omap_l4.c
+++ b/hw/omap_l4.c
@@ -146,6 +146,12 @@
     return bus;
 }
 
+target_phys_addr_t omap_l4_region_base(struct omap_target_agent_s *ta,
+                                       int region)
+{
+    return ta->bus->base + ta->start[region].offset;
+}
+
 static uint32_t omap_l4ta_read(void *opaque, target_phys_addr_t addr)
 {
     struct omap_target_agent_s *s = (struct omap_target_agent_s *) opaque;