jtag: move declaration outside function

jtag: move declaration outside function

The function jtag_debug_state_machine_() is only used by a static
inline function and declared inside it as private.
The static analyser 'sparse' complains that the function is
defined as global but not cross checked against a prototype in an
include file.

Move the declaration outside the inline function so it get visible
by interface.c, which already includes interface.h
While there, change the argument type from 'unsigned' to 'unsigned
int' to pass checkpatch check.

Change-Id: Ia5dfb92dc4bc6d52ead4f0cb8c68319c83ff85b0
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/7672
Tested-by: jenkins