rename jtag_nsrst_delay as adapter_nsrst_delay

Globally rename "jtag_nsrst_delay" as "adapter_nsrst_delay", and move it
out of the "jtag" command group ...  it needs to be used with non-JTAG
transports

Includes a migration aid (in jtag/startup.tcl) so that old user scripts
won't break.  That aid should Sunset in about a year.

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

src/jtag/startup.tcl

@@ -83,4 +83,5 @@ proc srst_asserted {} {
 # FIXME phase these aids out after about April 2011
 #
 proc jtag_khz args { eval adapter_khz $args }
+proc jtag_nsrst_delay args { eval adapter_nsrst_delay $args }
 # END MIGRATION AIDS