Sparc64: replace tsptr with helper routine

tl and tsptr of members sparc64 cpu state must be changed
simultaneously to keep trap state window in sync with current
trap level. Currently translation of store to tl does not change
tsptr, which leads to corrupt trap state on corresponding
trap level.

This patch removes tsptr from sparc64 cpu state and replaces
all uses with call to helper routine.

Changes v0->v1:
- reimplemented helper routine with tcg generator
- on cpu reset trap type and pstate are populated with power-on reset
values, including tl=maxtl

Signed-off-by:  <igor.v.kovalenko@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>