arm: mach-k3: Use JTAD_ID register for device identification

JTAG ID register is defined by IEEE 1149.1 for device identification.
Use this JTAG ID register for identifying AM65x[0] and J721E[1] devices
instead of using SoC specific registers.

[0] http://www.ti.com/lit/ug/spruid7e/spruid7e.pdf
[1] http://www.ti.com/lit/ug/spruil1a/spruil1a.pdf



Reported-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>