bcachefs: Fix MEAN_AND_VARIANCE kconfig options

	select XXHASH

	select SRCU

	select SYMBOLIC_ERRNAME

	select MEAN_AND_VARIANCE

	help

	The bcachefs filesystem - a modern, copy on write filesystem, with

	support for multiple devices, compression, checksumming, etc.

config MEAN_AND_VARIANCE_UNIT_TEST

	tristate "mean_and_variance unit tests" if !KUNIT_ALL_TESTS

	depends on KUNIT

	select MEAN_AND_VARIANCE

	depends on BCACHEFS_FS

	default KUNIT_ALL_TESTS

	help

	  This option enables the kunit tests for mean_and_variance module.