kbuild: scripts/genksyms/lex.l: add %option noinput

gcc 4.3 correctly determines that input() is unused and gives the
following warning:

<--  snip  -->

...
  HOSTCC  scripts/genksyms/lex.o
scripts/genksyms/lex.c:1487: warning: ‘input’ defined but not used
...

<--  snip  -->

Fix it by adding %option noinput to scripts/genksyms/lex.l and
regeneration of scripts/genksyms/lex.c_shipped.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>