jtag: add -ir-bypass option to newtap

Some devices with an internal multi-tap JTAG router require a vendor
specific bypass instruction to bypass the master TAP when addressing
slave taps internal to the same device. On these devices the standard
bypass instruction bypasses the whole device.

Change-Id: I4506f0e67c9e4dfe39b7fa18c63d67900313e594
Signed-off-by: Henrik Nordström <henrik.nordstrom@addiva.se>
Reviewed-on: https://review.openocd.org/c/openocd/+/8041
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins

doc/openocd.texi

@@ -4424,6 +4424,10 @@ there seems to be no problems with JTAG scan chain operations.
 register during initial examination and when checking the sticky error bit.
 This bit is normally checked after setting the CSYSPWRUPREQ bit, but some
 devices do not set the ack bit until sometime later.
+@item @code{-ir-bypass} @var{NUMBER}
+@*Vendor specific bypass instruction, required by some hierarchical JTAG
+routers where the normal BYPASS instruction bypasses the whole router and
+a vendor specific bypass instruction is required to access child nodes.
 @end itemize
 @end deffn