tcl/interface: add linuxgpiod cfg for Aspeed AST2600

tcl/interface: add linuxgpiod cfg for Aspeed AST2600

Add linuxgpiod cfg for Aspeed AST2600 for a case if JTAG master needs
to be implemented using linuxgpiod intead of hardware JTAG master mode.

These AST2600 GPIOs will be mapped to JTAG/SWD signals.
+-----------+-------------+-------------+
| signal    | GPIO name   | gpio offset |
+-----------+-------------+-------------+
| TCK/SWCLK | GPIOI2      | 66          |
| TMS/SWDIO | GPIOI3      | 67          |
| TDI       | GPIOI1      | 65          |
| TDO       | GPIOI4      | 68          |
| nTRST     | GPIOI0      | 64          |
+-----------+-------------+-------------+

Signed-off-by: Jae Hyun Yoo <quic_jaehyoo@quicinc.com>
Change-Id: I19278402b0895be12d38c0ecea8fdbc56fd491b8
Reviewed-on: https://review.openocd.org/c/openocd/+/7112
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins