[intrinsics/riscv64] Fix missing flags on set round

FeSetRound macro insns should be marked as having side effects since
they modify the float rounding mode on the host.

Bug: 291126259
Test: mm and berberis_host_tests
Change-Id: Id65ef967011cfb6544efcf0f1a8d8b5e51bbc973
1 file changed