kbuild: fix documentation in makefiles.txt
kbuild: fix documentation in makefiles.txt

Small error had sneaked in with respect to use
of LDFLAGS_$@. LDFLAGS_$@ is not valid in normal
kbuild files so do not say so.
Fix a reference bug too.

Signed-off-by: Sam Ravnborg <f16bed56189e249fe4ca8ed10a1ecae60e8ceac0@ravnborg.org>

KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas