tcl: target: am437x.cfg: pass correct dbgbase

tcl: target: am437x.cfg: pass correct dbgbase

Since commit ec9ccaa28849 (arm_adi_v5: make dap_lookup_cs_component()
traverse subtables and handle multicore) AM437x devices can't be used
with OpenOCD anymore. The reason is that dbgbase used to be set to zero
before that commit and that just happens to work with AM437x devices.

A more robust solution is to pass correct dbgbase when creating the
target, which this commit does.

Signed-off-by: Felipe Balbi <balbi@ti.com>
Change-Id: Iaf2617804324de8094b25137943e08b84f14c75f
Reviewed-on: http://openocd.zylin.com/2602
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>