broadcom/compiler: remove always true condition
qpu.raddr_b
is an unsigned int, so it is always positive, even after
casting to signed int.
Thus, (int) inst->qpu.raddr_b >= -16
is always true, so it can be
removed from the condition.
Fixes CID#1438117 "Operands don't affect result (CONSTANT_EXPRESSION_RESULT)":
"result_independent_of_operands: (int)inst->qpu.raddr_b >= -16 is always true regardless of the values of its operands. This occurs as the logical first operand of "&&".