clocksource/drivers/timer-ti-dm: Remove an unused field in struct dmtimer

In "struct dmtimer", the 'rate' field is unused.
Remove it.

Found with cppcheck, unusedStructMember.

Signed-off-by: Christophe JAILLET <[e-mail]>
Signed-off-by: Daniel Lezcano <[e-mail]>
Link: https://lore.kernel.org/r/c9f7579922[e-mail]

drivers/clocksource/timer-ti-dm.c

···
 	void __iomem	*func_base;	/* function register base */
 
 	atomic_t enabled;
-	unsigned long rate;
 	unsigned reserved:1;
 	unsigned posted:1;
 	unsigned omap1:1;