Group the parameters passed in to create SAs.

This change groups encryption parameters, authentication
parameters, and mark match parameters into three parameters,
encryption, auth_trundc, and mark.

This removes a fair bit of boilerplate code and allows callers
to be more explicit about what they want.

Test: all xfrm tests pass on android-4.9
Change-Id: Ia8e084d49db91aff746f4ffbc2c62cfb2e399f63