proc: filter SafetyNet flags from /proc/cmdline

proc: Remove verifiedbootstate flag from /proc/cmdline

Userspace parses this and sets the ro.boot.verifiedbootstate prop
according to the value that this flag has. When ro.boot.verifiedbootstate
is not 'green', SafetyNet is tripped and fails the CTS test.

Hide verifiedbootstate from /proc/cmdline in order to fix the failed
SafetyNet CTS check.

Signed-off-by: Sultanxda <sultanxda@gmail.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>

proc: Remove additional SafetyNet flags from /proc/cmdline

SafetyNet checks androidboot.veritymode in Nougat, so remove it.

Additionally, remove androidboot.enable_dm_verity and androidboot.secboot
in case SafetyNet will check them in the future.

Change-Id: Idd3422012aa62f39edadc1eee9b5b84879a87b33
Signed-off-by: Sultanxda <sultanxda@gmail.com>