perf: restrict libunwind dependency to archs that actually support libunwind

Allow building perf on uncommon targets again.

Depending on the kernel version, not all of these archs will actually use
libunwind in perf. Still, it seems simpler and less error-prone to use the
same list that is defined in the libunwind package.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>

package/devel/perf/Makefile

@@ -26,7 +26,7 @@ include $(INCLUDE_DIR)/package.mk
 define Package/perf
   SECTION:=devel
   CATEGORY:=Development
-  DEPENDS:= +libelf1 +libdw +libunwind +libpthread +librt +objdump @!LINUX_3_18 @!IN_SDK @!TARGET_arc770 @KERNEL_PERF_EVENTS
+  DEPENDS:= +libelf1 +libdw +(mips||mipsel||powerpc||i386||x86_64||arm||aarch64):libunwind +libpthread +librt +objdump @!LINUX_3_18 @!IN_SDK @!TARGET_arc770 @KERNEL_PERF_EVENTS
   TITLE:=Linux performance monitoring tool
   VERSION:=$(LINUX_VERSION)-$(PKG_RELEASE)
   URL:=http://www.kernel.org