FLIS IP since now gets its own ACPI ID.
Drop PRP0001 workaround in favour of official ACPI HID.

Corresponding kernel commit dabd4bc6de2b

	pinctrl: intel: merrifield: Introduce ACPI device table

in the pin control subsystem tree [1] targeting v4.16.

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl.git/commit/?h=for-next&id=dabd4bc6de2bReviewed-by: NBin Meng <bmeng.cn@gmail.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>