arc: Update exception & interrupt handling for ARCv2

arc: Update exception & interrupt handling for ARCv2

Initially IVT for ARCv2 was simply copypasted from ARCompact
with some selected fixes so basic stuff works.

Now we update it with more ARCv2 specific vectors like
 * Software Interrupt
 * Division by zero
 * Data cache consistency error
 * Misaligned access

Also normal interrupts are now implemented properly and extened to
all possible 240 items.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>