Resolve incomplete fix for SMP authentication bypass

Fix for b/25992313 was landed correctly on main, but in older branches
SMP contains identical functions smp_proc_init and smp_proc_rand, both
of which exhibit the problem, and only the former of which was patched.
This allows the problem to still appear on branches from sc-dev to
udc-dev.

Add the logic to smp_proc_rand.

Bug: 251514170
Test: m com.android.btservices
Tag: #security
Ignore-AOSP-First: security
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:16a745956dbaff2d37d0e7afdf662314ea379f29)
Merged-In: I51e99c18a322a29632a6cac09ddb2b07bea482fc
Change-Id: I51e99c18a322a29632a6cac09ddb2b07bea482fc