rtc: lib: check whether tm->tm_year in int32 range

When setting rtc alarm (RTC_WKALM_SET), the tm_year is not checked if it
is in suiteable range. Use INT_MAX - 1900 to check it.

UBSAN: Undefined behaviour in drivers/rtc/rtc-lib.c:119:30
signed integer overflow:
2147483647 + 1900 cannot be represented in type 'int'
CPU: 1 PID: 20994 Comm: syz-executor0 Not tainted 4.19.18-514.55.6.9.x86_64
+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1
04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xca/0x13e lib/dump_stack.c:113
 ubsan_epilogue+0xe/0x81 lib/ubsan.c:159
 handle_overflow+0x193/0x1e2 lib/ubsan.c:190
 rtc_tm_to_time64+0x267/0x280 drivers/rtc/rtc-lib.c:119
 rtc_tm_to_ktime+0x16/0x70 drivers/rtc/rtc-lib.c:129
 rtc_set_alarm+0x1a9/0x2d0 drivers/rtc/interface.c:466
 rtc_dev_ioctl+0x6db/0x810 drivers/rtc/rtc-dev.c:380
 vfs_ioctl fs/ioctl.c:46 [inline]
 do_vfs_ioctl+0x1a5/0x10b0 fs/ioctl.c:690
 ksys_ioctl+0x89/0xa0 fs/ioctl.c:705
 __do_sys_ioctl fs/...