svga: remove TGSI_OPCODE_BREAKC instruction translation

While initially that opcode probably was meant for something along the
lines of sm3 break_comp it has never worked that way (not even the
argument count was right) and now the opcode has quite different
semantics so just remove it. (Discovered by Jose Fonseca)

src/gallium/drivers/svga/svga_tgsi_insn.c

    switch (opcode) {
    case TGSI_OPCODE_ABS:        return SVGA3DOP_ABS;
    case TGSI_OPCODE_ADD:        return SVGA3DOP_ADD;
-   case TGSI_OPCODE_BREAKC:     return SVGA3DOP_BREAKC;
    case TGSI_OPCODE_DP2A:       return SVGA3DOP_DP2ADD;
    case TGSI_OPCODE_DP3:        return SVGA3DOP_DP3;
    case TGSI_OPCODE_DP4:        return SVGA3DOP_DP4;