vkd3d-shader/hlsl: Don't map src swizzles for SM1 dp3 and dp4 ops.

Without this patch, dp3 and dp4 map src swizzles to the dst writemask, which is not correct.

Before b84f560b, these ops worked despite this, because the dst register had, incorrectly, the full writemask.

To solve this problem, write_sm1_binary_op_dot() is introduced, similarly to write_sm4_binary_op_dot().

This was pointed out by @nsivov in https://bugs.winehq.org/show_bug.cgi?id=54522.