init.hardware.rc: Improve I/O performance

It is known that I/O performance is suboptimal if the CFQ group_idle
parameter is not zero or if the BFQ slice_idle parameter is not zero.
Since Redbull devices use the CFQ I/O scheduler and since slice_idle is
a BFQ parameter, write 0 into the group_idle parameter.

Bug: 213617178
Bug: 313578691
Signed-off-by: Bart Van Assche <bvanassche@google.com>
(cherry picked from https://android-review.googlesource.com/q/commit:c71a1663431b7342a1fb2a4ca5bc67fbf1938672)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:4036863e853011021bde6a6bde9fda001030613d)
Merged-In: I02429876790a6456ca957ff7c38f0c8bf88127f9
Change-Id: I02429876790a6456ca957ff7c38f0c8bf88127f9