iio: accel: kxcjk-1013: Fix defined but unused warning

Noticed when compiling with CONFIG_PM_RUNTIME not set:
kxcjk-1013.c: warning: ‘kxcjk1013_get_startup_times’ defined but not used [-Wunused-function]

Introduced by commit 124e1b1d (iio: accel: kxcjk-1013: support runtime pm).

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>