drivers: rtc: sam: Fix missing function #146517

Job	Run time
twister-build-prep	2m 36s
twister-build (1)	31m 1s
twister-build (2)	28m 33s
twister-build (3)	26m 28s
twister-build (4)	34m 2s
twister-build (5)	19m 47s
twister-build (6)	19m 46s
twister-build (7)	32m 7s
Publish Unit Tests Results	16s
Check Twister Status / all jobs passed	2s
	3h 14m 38s

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