sh: Fix up link time defsym warnings.

sh-linux-gnu-ld:--defsym 'jiffies=jiffies_64': ignoring invalid character `'' in expression

For some reason ld has recently started complaining about the quotes, so just
get rid of them, we don't need them for anything anyways.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>