ANDROID: cpufreq: add macro guard to protect vendor hook

To fix build fail of patch [1] by adding the macro guard to protect the
vendor hook register caller and its callback function.

The report log [2] shows build fail due to the absence of macro
definition of CONFIG_ANDROID_VENDOR_HOOKS.

[1] https://android-review.googlesource.com/c/kernel/common/+/2357403
[2] https://storage.tuxsuite.com/public/clangbuiltlinux/continuous-integration2/builds/2JGC8dCPsZEMPlkPuFiztM7k46n/build.log



Bug: 260537724
Change-Id: I33fe623e3cbe82647bda7c43d36e66ce8e22b11f
Signed-off-by: Jia-Wei Chang <jia-wei.chang@mediatek.com>