Davinci: jtag_id - use ioremap()

This patch replaces the jtag id base info in davinci_soc_info with a physical
address which is then ioremap()ed within common code.

This patch (in combination with a similar change for PSC) will allow us to
eliminate the SYSCFG nastiness in DA8xx code.

Signed-off-by: Cyril Chemparathy <cyril@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>