prism54: isl_38xx: Replace 'struct timeval'

'struct timeval' uses a 32-bit seconds field which will overflow in
year 2038 and beyond. This patch is part of a larger effort to remove
all instances of 'struct timeval' from the kernel and replace them
with 64-bit timekeeping variables.
The patch also fixes the debug printf specifier to avoid the
seconds value being truncated.
The patch was build-tested / debugged by removing the
"if VERBOSE > SHOW_ERROR_MESSAGES" guards.

Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>