freedreno: avoid conditional ib in fd6_emit_tile
CP_REG_TEST (or any command that reads registers) is slow on a618 (gen1). Since SQE can early return, we don't necessarily need emit_conditional_ib in fd6_emit_tile.
We still CP_REG_TEST twice for load and store when there is no clear. Not sure if we can simply drop emit_conditional_ib instead?
glmark2 score goes from 943 to 1067.