R600/SI: Remove redundant setting of bits on instructions.

neverHasSideEffects is deprecated, and hasSideEffects = 0 is already
set on the base classes of the basic ALU instruction classes. The
base classes also already set mayLoad = 0 and mayStore = 0

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214283 91177308-0d34-0410-b5e6-96231b3b80d8