cris: Drop reference to get_cmos_time()

Function get_cmos_time() was removed with commit 657926a83df9 ("cris:
time: Cleanup of persistent clock stuff"). The remaining reference to
it may cause the following build error.

arch/cris/kernel/built-in.o:(___ksymtab+get_cmos_time+0x0):
	undefined reference to `get_cmos_time'
Makefile:946: recipe for target 'vmlinux' failed

Fixes: 657926a83df9 ("cris: time: Cleanup of persistent clock stuff")
Cc: Xunlei Pang <pang.xunlei@linaro.org>
Cc: Rabin Vincent <rabin@rab.in>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jesper Nilsson <jespern@axis.com>