hw: use context-area base that is ok for VEA9X4-TZ

On VEA9X4-TZ, the context-area overlaps with the virtual area of the
text, data and bss. However, we can't simply change the link address as
the core image (used physically respectively 1:1 mapped) needs to be in
this particular RAM-region as it is the only one that can be protected
against a VM. Thus I've moved the context area to a place where it
shouldn't disturb any HW-platform.

Fixes #1337

repos/base-hw/include/base/native_types.h

@@ -112,7 +112,7 @@ namespace Genode
 		 * Thread-context area configuration.
 		 */
 		static constexpr addr_t context_area_virtual_base() {
-			return 0x40000000UL; }
+			return 0xe0000000UL; }
 		static constexpr addr_t context_area_virtual_size() {
 			return 0x10000000UL; }