feat(versal-net): add jtag dcc support

feat(versal-net): add jtag dcc support

Add support for JTAG Debug Communication Channel(DCC), using the dcc
console driver, for Versal NET platform.
UART0/UART1 is not configured when the JTAG DCC is used as console for
the platform.
Though DCC is not using any UART, VERSAL_NET_UART_BASE needs
to be defined in the platform code. If its not defined, build errors
are observed.
Now VERSAL_NET_UART_BASE by default points to UART0 base.
Check for valid console(pl011, pl011_0, pl011_1, dcc) is
being done in the platform makefile, the error condition in
setting the value of VERSAL_NET_UART_BASE is redundant, thus the error
message is removed from the code.

Change-Id: I1085433055abea13526230cff4d4183ff7a01477
Signed-off-by: Akshay Belsare <akshay.belsare@amd.com>