lib: math: Move KUnit tests into tests/ subdir

This patch is a follow-up task from a discussion stemming from point 3
in a recent patch introducing the int_pow kunit test [1] and
documentation regarding kunit test style and nomenclature [2].

Colocate all kunit test suites in lib/math/tests/ and
follow recommended naming convention for files <suite>_kunit.c
and kconfig entries CONFIG_<name>_KUNIT_TEST.

Link: https://lore.kernel.org/all/CABVgOS=-vh5TqHFCq_jo=ffq8v_nGgr6JsPnOZag3e6+19ysxQ@mail.gmail.com/ [1]
Link: https://docs.kernel.org/dev-tools/kunit/style.html [2]

Signed-off-by: Luis Felipe Hernandez <luis.hernandez093@gmail.com>
Acked-by: Nicolas Pitre <npitre@baylibre.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Rae Moar <rmoar@google.com>
Link: https://lore.kernel.org/r/20241202075545.3648096-2-davidgow@google.com
Signed-off-by: Kees Cook <kees@kernel.org>

lib/Kconfig.debug

@@ -3166,7 +3166,7 @@ config TEST_OBJPOOL
 
 	  If unsure, say N.
 
-config INT_POW_TEST
+config INT_POW_KUNIT_TEST
 	tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS
 	depends on KUNIT
 	default KUNIT_ALL_TESTS

lib/math/Makefile

@@ -5,8 +5,7 @@ obj-$(CONFIG_CORDIC)		+= cordic.o
 obj-$(CONFIG_PRIME_NUMBERS)	+= prime_numbers.o
 obj-$(CONFIG_RATIONAL)		+= rational.o
 
-obj-$(CONFIG_INT_POW_TEST)  += tests/int_pow_kunit.o
 obj-$(CONFIG_TEST_DIV64)	+= test_div64.o
 obj-$(CONFIG_TEST_MULDIV64)	+= test_mul_u64_u64_div_u64.o
-obj-$(CONFIG_RATIONAL_KUNIT_TEST) += rational-test.o
-obj-$(CONFIG_INT_SQRT_KUNIT_TEST) += tests/int_sqrt_kunit.o
+
+obj-y += tests/

lib/math/tests/Makefile

@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
-obj-$(CONFIG_INT_POW_TEST) += int_pow_kunit.o
-obj-$(CONFIG_INT_SQRT_KUNIT_TEST) += int_sqrt_kunit.o
+obj-$(CONFIG_INT_POW_KUNIT_TEST)	+= int_pow_kunit.o
+obj-$(CONFIG_INT_SQRT_KUNIT_TEST)	+= int_sqrt_kunit.o
+obj-$(CONFIG_RATIONAL_KUNIT_TEST)	+= rational_kunit.o