defconfig: lahaina: Enable subsystem_sleep_stats driver

subsystem_sleep_stats provide IOCTL interface to
statistical information and can be useful where debugfs
not present.

This change enables this driver.

Change-Id: Id53650408d00781aece49aa29d87b389cd409d43
Signed-off-by: Tushar Nimkar <tnimkar@codeaurora.org>