uclibc: clean-up test suite build command

Starting from uClibc 0.9.32 "test_compile" target builds tests flawlessly.
For 0.9.31 it lead to build failure, but now when AVR32 support was dropped
I think this change worth applying.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Peter Korsgaard <peter@korsgaard.com>
Cc: Gustavo Zacarias <gustavo@zacarias.com.ar>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Thomas De Schampheleire <patrickdepinguin@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/uclibc/uclibc.mk

@@ -398,12 +398,10 @@ endef
 
 ifeq ($(BR2_UCLIBC_INSTALL_TEST_SUITE),y)
 define UCLIBC_BUILD_TEST_SUITE
-	$(MAKE1) -C $(@D)/test \
+	$(MAKE1) -C $(@D) \
 		$(UCLIBC_MAKE_FLAGS) \
-		ARCH_CFLAGS=-I$(STAGING_DIR)/usr/include \
 		UCLIBC_ONLY=1 \
-		TEST_INSTALLED_UCLIBC=1 \
-		compile
+		test_compile
 endef
 endif