unicore32-softmmu: Make UniCore32 cpuid & exceptions correct and runable

This patch initializes the cpuid to exactly correct value because
linux kernel will check it.
In addition, the exception types are specified in proper situations.
Then it could make exceptions generated correctly and timely.

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
