finish removing deprecated/obsolete commands

It's been about a year since these were deprecated and, in most
cases, removed.  There's no point in carrying that documentation,
or backwards compatibility for "jtag_device" and "jtag_speed",
around forever.  (Or a few remnants of obsolete code...)

Removed a few obsolete uses of "jtag_speed":

 - The Calao stuff hasn't worked since July 2008.  (Those Atmel
   targets need to work with a 32KHz core clock after reset until
   board-specific init-reset code sets up the PLL and enables a
   faster JTAg clock.)
 - Parport speed controls don't actually work (tops out at about
   1 MHz on typical HW).
 - In general, speed controls need to live in board.cfg files (or
   sometimes target.cfg files), not interface.cfg ...

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

src/target/arm7_9_common.c

@@ -38,7 +38,6 @@
 
 
 int arm7_9_debug_entry(target_t *target);
-int arm7_9_enable_sw_bkpts(struct target_s *target);
 
 /* command handler forward declarations */
 int handle_arm7_9_write_xpsr_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);