linux/clk.h: use correct kernel-doc notation for 2 functions

Fix kernel-doc notation for 2 functions so that the generated
html is correct. Currently it skips all text between the
':' and the '-', so "[un]register a clock rate" is missing.

Fixes: 86bcfa2e ("clk: add pr_debug & kerneldoc around clk notifiers")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-clk@vger.kernel.org
Link: https://lore.kernel.org/r/20210107023304.24442-1-rdunlap@infradead.org


Signed-off-by: Stephen Boyd <sboyd@kernel.org>