Doc (mostly) update for jtag_khz:
 - switch to @deffn syntax
 - add entry for "jtag_rclk"
 - move deprecated "jtag_speed" into collection of deprecated calls

And for ft2232, don't be the only adapter to *log* an error if RTCK
is requested; it's already reported properly, like any other nonfatal
command parameter.  "jtag_rclk" just works as expected, without any
scarey messages.


git-svn-id: svn://svn.berlios.de/openocd/trunk@1910 b42882b7-edfa-0310-969c-e2dbd0fdcd60