ARM: OMAP2+: Remove unused max number of timers definition

The OMAP2+ timer code has a definition for the maximum number of timers that
OMAP2+ devices have. This defintion is not used anywhere in the code and
appears to be left over. Furthermore the definition is not accurate for OMAP4
devices that only have 11 timers available because the 12th timer is reserved
as a secure timer and for OMAP3 devices the 12th timer is not available on
secure devices. Therefore, remove this definition.

Signed-off-by: Jon Hunter <jon-hunter@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>