kbuild: remove wrong 'touch' in adjust_autoksyms.sh

The comment mentions it creates autoksyms.h in case it is missing,
but the actual code touches it when it does exists.

The build system creates it anyway because <linux/export.h> and
<asm-generic/export.h> need it.

The code would not have worked as intended, and people have not
noticed it.  This is a proof that we can simply remove it.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NNicolas Pitre <nico@linaro.org>

scripts/adjust_autoksyms.sh

@@ -48,9 +48,6 @@ case "${KCONFIG_CONFIG}" in
 	. "./${KCONFIG_CONFIG}"
 esac
 
-# In case it doesn't exist yet...
-if [ -e "$cur_ksyms_file" ]; then touch "$cur_ksyms_file"; fi
-
 # Generate a new ksym list file with symbols needed by the current
 # set of modules.
 cat > "$new_ksyms_file" << EOT