pata_pdc2027x: Use 64-bit timekeeping

Function pdc_detect_pll_input_clock uses 'struct timeval'
to measure start and end times, used to compute the pll_clock value.
'struct timeval' on 32-bit systems will have its tv_sec field
overflow in year 2038 and beyond. This patch uses 'ktime_t'
(which uses 64 bits for seconds) for start and end times instead.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Tejun Heo <tj@kernel.org>