hwpstate_amd: Fix compile error

Add parentheses between OR and AND operator to pass the compiler check.

Approved by: lwhsu (mentor)
Fixes: 3e6e4e4a0d42 ("hwpstate: add CPPC support for pstate driver on AMD")
MFC aftert: 2 weeks
Differential Revision: https://reviews.freebsd.org/D54465