init/initramfs.c: fix "symbol shadows an earlier one" noise

The symbol 'count' is a local global variable in this file.  The function
clean_rootfs() should use a different symbol name to prevent "symbol
shadows an earlier one" noise.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>