selftests/alsa: Fix circular dependency involving global-timer

The pattern rule `$(OUTPUT)/%: %.c` inadvertently included a circular
dependency on the global-timer target due to its inclusion in
$(TEST_GEN_PROGS_EXTENDED). This resulted in a circular dependency
warning during the build process.

To resolve this, the dependency on $(TEST_GEN_PROGS_EXTENDED) has been
replaced with an explicit dependency on $(OUTPUT)/libatest.so. This change
ensures that libatest.so is built before any other targets that require it,
without creating a circular dependency.

This fix addresses the following warning:

make[4]: Entering directory 'tools/testing/selftests/alsa'
make[4]: Circular default_modconfig/kselftest/alsa/global-timer <- default_modconfig/kselftest/alsa/global-timer dependency dropped.
make[4]: Nothing to be done for 'all'.
make[4]: Leaving directory 'tools/testing/selftests/alsa'

Cc: Mark Brown <[email protected]>
Cc: Jaroslav Kysela <[email protected]>
Cc: Takashi Iwai <[email protected]>
Cc: Shuah Khan <[email protected]>
Signed-off-by: Li Zhijian <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Takashi Iwai <[email protected]>

Author: zhijianli88

tools/testing/selftests/alsa/Makefile

@@ -27,5 +27,5 @@ include ../lib.mk
 $(OUTPUT)/libatest.so: conf.c alsa-local.h
 	$(CC) $(CFLAGS) -shared -fPIC $< $(LDLIBS) -o $@
 
-$(OUTPUT)/%: %.c $(TEST_GEN_PROGS_EXTENDED) alsa-local.h
+$(OUTPUT)/%: %.c $(OUTPUT)/libatest.so alsa-local.h
 	$(CC) $(CFLAGS) $< $(LDLIBS) -latest -o $@