arc: Add aux-reg and core-reg Jim commands

Those replace older read-aux-reg, write-aux-reg, read-core-reg and
write-core-reg command. Unlike old command and generic OpenOCD "reg" command
those command returns register value as a result for reads, instead of
printing it. This allows to use register value in scripts. Those commands
accept only register number - no register names.  That also means that they
can work with registers unknown to OpenOCD register list.

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
arc: Remove obsolete register commands

Use (aux|core)-reg <regnum> [<value>] instead.

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
arc: Support custom reset-assert handlers

ARC development platforms don't have SRST signals so current assert_reset
does nothing for them and they are left in the non-reset state. Custom
rest-assert handlers will do a proper reset for us.

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
arc: Add a procedure for software reset

Add cpu/arc script with a software reset procedure. Development boards by
Synopsys do not support SRST, so we can do only a software reset and this
function implements it in a way described in PRM.

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
arc: Use new reset procedure in our development boards

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
ft2232: Fix EM Starter Kit v2 support

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>