hp_sdc_rtc: fix broken ioctl conversion

Commit 55929332 "drivers: Push down BKL into various drivers"
introduced a regression in hp_sdc_rtc, caused by a missing
change of the .unlocked_ioctl pointer to the newly introduced
function.

Fixes:

	drivers/input/misc/hp_sdc_rtc.c:681: warning: initialization from
	incompatible pointer type
	drivers/input/misc/hp_sdc_rtc.c:665: warning:
	‘hp_sdc_rtc_unlocked_ioctl’ defined but not used

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>