JTAG: shrink "scan_chain" output

Tweak the "scan_chain" output by removing column separators.  Also
remove the "current instruction" state ... which changes constantly.

Now its style resembles the "targets" output, and can even fit on
one line in standard terminals and in the PDF docs.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

doc/openocd.texi

@@ -2592,13 +2592,15 @@ debugging targets.)
 Here's what the scan chain might look like for a chip more than one TAP:
 
 @verbatim
-   TapName            Enabled IdCode     Expected   IrLen IrCap IrMask Instr
--- ------------------ ------- ---------- ---------- ----- ----- ------ -----
- 0 omap5912.dsp          Y    0x03df1d81 0x03df1d81 38    0     0      0x...
- 1 omap5912.arm          Y    0x0692602f 0x0692602f 4     0x1   0      0xc
- 2 omap5912.unknown      Y    0x00000000 0x00000000 8     0     0      0xff
+   TapName            Enabled IdCode     Expected   IrLen IrCap IrMask
+-- ------------------ ------- ---------- ---------- ----- ----- ------
+ 0 omap5912.dsp          Y    0x03df1d81 0x03df1d81    38 0x01  0x03
+ 1 omap5912.arm          Y    0x0692602f 0x0692602f     4 0x01  0x0f
+ 2 omap5912.unknown      Y    0x00000000 0x00000000     8 0x01  0x03
 @end verbatim
 
+OpenOCD can detect some of that information, but not all
+of it.  @xref{Autoprobing}.
 Unfortunately those TAPs can't always be autoconfigured,
 because not all devices provide good support for that.
 JTAG doesn't require supporting IDCODE instructions, and
@@ -2659,8 +2661,6 @@ The set of TAPs listed by this command is fixed by
 exiting the OpenOCD configuration stage,
 but systems with a JTAG router can
 enable or disable TAPs dynamically.
-In addition to the enable/disable status, the contents of
-each TAP's instruction register can also change.
 @end deffn
 
 @c FIXME!  "jtag cget" should be able to return all TAP