rtc: max77663: Added delay for awaiting buffer update

rtc: max77663: Added delay for awaiting buffer update

Added 14ms delay for awaiting buffer update. So there is no need to
check update buffer flag bit on RTC_UPDATE1 register.

Bug 849360

Signed-off-by: Jin Park <jinyoungp@nvidia.com>
Reviewed-on: http://git-master/r/50987
(cherry picked from commit 1879feec7231ec082e6133e2172566ad4ee43f66)
Change-Id: If54c6ea3744140b9886ace26f335b0c0ecb72bb2
Reviewed-on: http://git-master/r/54635
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

Rebase-Id: R7af025ac026c58ad7aa3d97038c04eb873658eca