Calculating the solubility of cuprous iodide
First of all, as MaxW pointed out in the above comment, your math seems to be wrong. From the the $K_\mathrm{sp}$ value given in your question:
$$s = \sqrt{K_\mathrm{sp}}= \sqrt{1.0 \times 10^{-12}}= \pu{1.0 \times 10^{-6} mol/L}= \pu{1.0 \times 10^{-6} mol/L} \times \frac{\pu{190.45 g}}{\pu{1 mol}}\times \frac{\pu{1000 mg}}{\pu{1 g}} \\ = \pu{0.190 mg/L}$$

Other than that, there seems to be a problem with online value of $K_\mathrm{sp}$ of $\ce{CuI}$. Some sites listed it as $1.1 \times 10^{-12}$ while other sites listed as $5.3 \times 10^{-12}$. However, I'd like the value $5.3 \times 10^{-12}$, because at least it's given in one of reliable sources (Ref.1).

If you use this value (instead of $1.1 \times 10^{-12}$), you'd get:

$$s = \sqrt{K_\mathrm{sp}}= \sqrt{5.3 \times 10^{-12}}= \pu{2.30 \times 10^{-6} mol/L}= \pu{2.30 \times 10^{-6} mol/L} \times \frac{\pu{190.45 g}}{\pu{1 mol}}\times \frac{\pu{1000 mg}}{\pu{1 g}} \\ = \pu{0.438 mg/L}$$

This value is in a good agreement with the literature value ($\pu{0.00042 g/L}$ at $\pu{25 ^\circ C}$; Ref.2), which listed the properties of $\ce{CuI}$ as:


  Copper (I) iodide is a dense, pure white solid, crystallizing with a zinc-blende structure below $300^\circ$. It is less sensitive to light than either the chloride or bromide, although passage of air over the solid at room temperature in daylight for $\pu{3 hr}$ results in the liberation of a small amount of iodine. It melts at $588^\circ$, boils at $1293^\circ$, and, unlike the other copper halides, is not associated in the vapor state. Being extremely insoluble ($\pu{0.00042 g/L}$ at $25^\circ$), it is not perceptibly decomposed by water. It is insoluble in dilute acids but dissolves in aqueous solutions of ammonia, potassium iodide, potassium cyanide, and sodium thiosulfate. It is decomposed by concentrated sulfuric and nitric acids.




References:


Steven S. Zumdahl, Donald J. DeCoste, In Chemical Principles; 8th Edition; Cengage Learning: Boston, MA, 2017, “Chapter 8: Applications of Aqueous Equilibria,” pp. 241–298 ($K_\mathrm{sp}$ of value $5.3 \times 10^{-12}$ is given for $\ce{CuI}$ in example 8.13, page 288). 
George B. Kauffman, Lawrence Y. Fang (Checked by N. Viswanathan, G. Townsend), “Chapter 2: Transition metal Complexes and Compounds – 20. Purification of Copper (I) Iodide,” In Inorganic Syntheses: Volume 22; Smith L. Holt Jr., Ed.; John Wiley &amp; Sons: New York, NY, 1983, pp. 103–107 (https://doi.org/10.1002/9780470132531.ch20).