radio: silabs: AF tune only if PI matches

During AF jump, check if PI of the AF frequency
matches with PI of original frequency before jumping
to the frequency.

CRs-fixed: 732781
Change-Id: Id8e34e2462ced09a4effeb8283543ee6fbdbdf42
Signed-off-by: Satish Kodishala <skodisha@codeaurora.org>