defconfig: msm8994: enable CONFIG_IRQ_TIME_ACCOUNTING

IRQ_TIME_ACCOUNTING provides for very fine grain profiling of irq
overhead. The scheduler can use it in task placement decisions and
in providing busy time to the CPU frequency governor.

Change-Id: Ib0b6419fd76ba0055c7f6b473ee846d1cf3520fb
Signed-off-by: Steve Muckle <smuckle@codeaurora.org>