sparc: kexec: Don't mess with the tl register

sparc: kexec: Don't mess with the tl register

I meddled with things I didn't fully understand while implementing commit
b43bc8f0 - "sparc64: add missing code for crash_setup_regs()"

I had changed the tl register in order to read tstate, tpc, etc. without
really knowing what I was doing. This can be a disaster if the crashing
thread takes another interrupt. Currently, the crash utitility doesn't
even use those values. They are found on the stack instead.

Orabug: 23585248

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
(cherry picked from commit 80eb7e28d3c719bbe3af56de5a5a8c68b764dbb9)
Signed-off-by: Allen Pais <allen.pais@oracle.com>