[openwrt/openwrt] perf: fix disabling BUILD_BPF_SKEL

[LEDE Commits]

nbd pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/cbfbac761a7ef94f6769eff5cf969cef67aa167c

commit cbfbac761a7ef94f6769eff5cf969cef67aa167c
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Sun Aug 31 23:48:10 2025 +0200

    perf: fix disabling BUILD_BPF_SKEL
    
    The makefile uses ifdef to check, so the variable needs to be empty
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 package/devel/perf/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package/devel/perf/Makefile b/package/devel/perf/Makefile
index c9b186cb86..c89eb08958 100644
--- a/package/devel/perf/Makefile
+++ b/package/devel/perf/Makefile
@@ -59,7 +59,7 @@ MAKE_FLAGS = \
 	NO_LIBCAP=1 \
 	NO_JEVENTS=1 \
 	NO_SHELLCHECK=1 \
-	BUILD_BPF_SKEL=0 \
+	BUILD_BPF_SKEL= \
 	CROSS_COMPILE="$(TARGET_CROSS)" \
 	CC="$(TARGET_CC)" \
 	LD="$(TARGET_CROSS)ld" \