generic: backport PPC boot wrapper VDSO executable stack fix
Backport upstream fix for PowerPC that fix VDSO executable stack warning
for the boot wrapper.
Fix the compilation error:
powerpc-openwrt-linux-musl-ld.bin: warning: div64.o: missing .note.GNU-stack section implies executable stack
powerpc-openwrt-linux-musl-ld.bin: NOTE: This behaviour is deprecated and will be removed in a future version of the linker
powerpc-openwrt-linux-musl-ld.bin: warning: arch/powerpc/boot/simpleImage.ws-ap3825i has a LOAD segment with RWX permissions
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>