Bluetooth: Enforce key size of 16 bytes on FIPS level
According to the spec Ver 5.2, Vol 3, Part C, Sec 5.2.2.8:
Device in security mode 4 level 4 shall enforce:
128-bit equivalent strength for link and encryption keys required
using FIPS approved algorithms (E0 not allowed, SAFER+ not allowed,
and P-192 not allowed; encryption key not shortened)
This patch rejects connection with key size below 16 for FIPS
level services.