jtag/drivers/jlink: better diagnostics for RCLK problems

jtag/drivers/jlink: better diagnostics for RCLK problems

The JLink protocol description doesn't really specify it for
JTAG-level commands but the real life evidence is that 0x01 error code
means "Adaptive clocking timeout" as it does for e.g. WRITE_MEM_ARM79.

Change-Id: I4e3b568742814271919f92d202713968c8fcccfb
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/2169
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>