Improve readability and maintainability by replacing a hardcoded string
allocation and formatting by the use of the devm_kasprintf() helper.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20190731132917.17607-4-geert+renesas@glider.beSigned-off-by: Linus Walleij <linus.walleij@linaro.org>