ACPI: CPPC: Fix _CPC register setting issue

ACPI: CPPC: Fix _CPC register setting issue

Since commit 60949b7b8054 ("ACPI: CPPC: Fix MASK_VAL() usage"), _CPC
registers cannot be changed from 1 to 0.

It turns out that there is an extra OR after MASK_VAL_WRITE(), which
has already ORed prev_val with the register mask.

Remove the extra OR to fix the problem.

Fixes: 60949b7b8054 ("ACPI: CPPC: Fix MASK_VAL() usage")
Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
Link: https://patch.msgid.link/20241113103309.761031-1-zhenglifeng1@huawei.com
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>