android: fiq_debugger: restrict access to critical commands.

Sysrq must be enabled via /proc/sys/kernel/sysrq as a security
measure to enable various critical fiq debugger commands that
either leak information or can be used as a system attack.

Default disabled, this will leave the reboot, reset, irqs, sleep,
nosleep, console and ps commands.  Reboot and reset commands
will be restricted from taking any parameters.  We will also
switch to showing the limited command set in this mode.

Signed-off-by: Mark Salyzyn <salyzyn@google.com>
Bug: 32402555
Change-Id: I3f74b1ff5e4971d619bcb37a911fed68fbb538d5
Git-repo: https://android.googlesource.com/kernel/msm


Git-commit: 1031836c0895f1f5a05c25efec83bfa11aa08ca9
Signed-off-by: Dennis Cagle <d-cagle@codeaurora.org>