Add aliased SRAM2 region in the L496 memory map

The SRAM2 on the L496 devices is aliased at 0x2004000. With this change, it's possible to read the SRAM2 contents at the aliased addresses.

src/gdbserver/gdb-server.c

@@ -449,7 +449,7 @@ static const char* const memory_map_template_L496 =
     "<memory-map>"
     "  <memory type=\"rom\" start=\"0x00000000\" length=\"0x%x\"/>"        // code = sram, bootrom or flash; flash is bigger
     "  <memory type=\"ram\" start=\"0x10000000\" length=\"0x10000\"/>"      // SRAM2 (64 KB)
-    "  <memory type=\"ram\" start=\"0x20000000\" length=\"0x40000\"/>"      // SRAM1 (256 KB)
+    "  <memory type=\"ram\" start=\"0x20000000\" length=\"0x50000\"/>"      // SRAM1 + aliased SRAM2 (256+64=320 KB)
     "  <memory type=\"flash\" start=\"0x08000000\" length=\"0x%x\">"
     "    <property name=\"blocksize\">0x800</property>"
     "  </memory>"