[klibc] mips: don't save floating point registers in setjmp / longjmp

Don't bother saving any floating point registers in setjmp or restoring
them in longjmp. This causes issues when compiling for the FPXX ABI, and
is unnessesary as klibc does not support floating point code.
Additionally, remove the unused parts of __jmp_buf.

Signed-off-by: James Cowgill <james.cowgill@mips.com>
Link: https://www.zytor.com/pipermail/klibc/2018-March/003983.html
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2 files changed