fix(rcar3-drivers): add integer overflow check

Add in the cert length calc function an integer overflow check

Signed-off-by: Tobias Rist <tobias.rist@joynext.com>
Signed-off-by: Yoshifumi Hosoya <yoshifumi.hosoya.wj@renesas.com>
Change-Id: I80e93582cd2d6006186e1573406b4945943b9422
1 file changed