rtc: tegra: change irq function name

rtc: tegra: change irq function name

suspend sanity need to check the timestamp of rtc isr.
This name should be aligned with the test.

Bug 1698877

Change-Id: I0ef053c8266336d5024c58e152b46c4bb27ecf60
Signed-off-by: Kerwin Wan <kerwinw@nvidia.com>
Reviewed-on: http://git-master/r/1021447
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Krishna Yarlagadda <kyarlagadda@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Sivaram Nair <sivaramn@nvidia.com>
Reviewed-by: Hayden Du <haydend@nvidia.com>