jtag/hla, jtag/stlink: switch to command 'adapter serial'

jtag/hla, jtag/stlink: switch to command 'adapter serial'

The driver hla defines the command 'hla_serial' to specify the
serial string of the adapter.
The driver st-link defines the command 'st-link serial' to specify
the serial string of the adapter.

Remove and deprecate the driver commands and use 'adapter serial'.

Change-Id: I9505c398a77125b1ebf4ba71da7baf4d663b75be
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/6657
Tested-by: jenkins