postgresql: disable spinlock for xtensa

Fixes:
http://autobuild.buildroot.net/results/fbf/fbf601af8b194effcad21a431ca447cb69c2bbd9/
http://autobuild.buildroot.net/results/822/822bd05bcb7384c671bfe13125db3a818982781a/
http://autobuild.buildroot.net/results/4ae/4ae938730a74f2be0f74fef8a99622f8f42742af/

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/postgresql/postgresql.mk

@@ -31,7 +31,7 @@ ifneq ($(BR2_TOOLCHAIN_HAS_THREADS),y)
 	POSTGRESQL_CONF_OPTS += --disable-thread-safety
 endif
 
-ifeq ($(BR2_microblazeel)$(BR2_microblazebe)$(BR2_nios2),y)
+ifeq ($(BR2_microblazeel)$(BR2_microblazebe)$(BR2_nios2)$(BR2_xtensa),y)
 	POSTGRESQL_CONF_OPTS += --disable-spinlocks
 endif