rtc-vr41xx: fix do_div() warning

drivers/rtc/rtc-vr41xx.c: In function 'vr41xx_rtc_irq_set_freq':
drivers/rtc/rtc-vr41xx.c:217: warning: comparison of distinct pointer types lacks a cast
drivers/rtc/rtc-vr41xx.c:217: warning: right shift count >= width of type
drivers/rtc/rtc-vr41xx.c:217: warning: passing argument 1 of '__div64_32' from incompatible pointer type
include/asm-generic/div64.h:35: note: expected 'uint64_t *' but argument is of type 'long unsigned int *'

Signed-off-by: Yoichi Yuasa <yuasa@linux-mips.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>