lib: move rtc-lib.c to lib

Function rtc_to_tm() is needed for FAT file system support even if we don't
have a real time clock. So move it from drivers/ to lib/.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

drivers/rtc/Makefile

@@ -7,7 +7,6 @@
 obj-$(CONFIG_$(SPL_TPL_)DM_RTC) += rtc-uclass.o
 
 obj-$(CONFIG_RTC_AT91SAM9_RTT) += at91sam9_rtt.o
-obj-y += rtc-lib.o
 obj-$(CONFIG_RTC_ARMADA38X) += armada38x.o
 obj-$(CONFIG_RTC_DAVINCI) += davinci.o
 obj-$(CONFIG_RTC_DS1302) += ds1302.o

lib/Makefile

@@ -135,6 +135,7 @@ obj-$(CONFIG_SSCANF) += sscanf.o
 endif
 
 obj-y += date.o
+obj-y += rtc-lib.o
 obj-$(CONFIG_LIB_ELF) += elf.o
 
 #