Add bpf_get_prandom_u32() to reference guide
Add bpf_get_prandom_u32() to reference guide

iovisor/bcc,mcaleavya/bcc,brendangregg/bcc,tuxology/bcc,iovisor/bcc,mcaleavya/bcc,iovisor/bcc,brendangregg/bcc,tuxology/bcc,mcaleavya/bcc,brendangregg/bcc,mcaleavya/bcc,mcaleavya/bcc,tuxology/bcc,brendangregg/bcc,tuxology/bcc,brendangregg/bcc,iovisor/bcc,tuxology/bcc,iovisor/bcc