Target memory map format

Hi,

The current target memory map format specified here:

https://sourceware.org/gdb/onlinedocs/gdb/Memory-Map-Format.html#Memory-Map-
Format

seems to map on to the memory region commands:

https://sourceware.org/gdb/onlinedocs/gdb/Memory-Region-Attributes.html

However, there doesn't seem to be a way to specify attributes such as the
memory access size or caching, from the memory map.

Would a patch that added support for additional properties be welcome? E.g:

<memory type="ram" start="addr" length="length">
            <property name="accesssize">any|8|16|32|64</property>
            <property name="cache">true|false</property>
</memory>

Also, the DTD in the documentation describes a "device" element:

<!ATTLIST memory        type    CDATA   #REQUIRED
                             start   CDATA   #REQUIRED
                             length  CDATA   #REQUIRED
                             device  CDATA   #IMPLIED>

However, I can't see any references to "device" in memory-map.c. Any idea
what it's for? 

Cheers,
Jon