Toshiba TMPA900 config: Fix incorrect working area.

Toshiba TMPA900 config: Fix incorrect working area.

The Toshiba TMPA900 series (TMPA900/901) only has internal RAM regions
RAM-0 (16kB) and RAM-1 (8kB) which we can use as working area.

This is probably a copy-paste error from tmpa910.cfg, which has the
correct values and sizes for the TMPA910 series (TMPA910/911/912/913):
there are RAM-0, RAM-1, and RAM-2 (each 16kB).

Also, change "built-in RAM" to "internal RAM" to match what the
datasheet uses.

Change-Id: I993cd6b7fadc28cf34e5cc18426bb2bb42597670
Signed-off-by: Uwe Hermann <uwe@hermann-uwe.de>
Reviewed-on: http://openocd.zylin.com/34
Tested-by: jenkins
Reviewed-by: Peter Stuge <peter@stuge.se>