Module signing and dm-verity needs key pair to be generated
using openssl. Add keygen file which is needed to generate
keys using openssl.
This is just snapshot of kalama's gh_ctrl driver from
'commit 5beb98404269 ("Merge "i3c: i3c-master-msm-geni: Fix
IBI for invalid device OR handler"")'from msm-5.15 branch.
Change-Id: I6d785f2a1695bf59969b7eba4f3f7a5df6342bf9
Signed-off-by: Peng Yang <quic_penyan@quicinc.com>