ARM: OMAP2+: Replace space with underscore in the name field of system timers

Depending on the bootloader, passing command-line arguments
with spaces may have issues. Some bootloaders doesn't seem
to pass along the quotes, passing only 'gp' part of the string,
which leads to wrong override configuration.

The only affected kernel parameter configuration for OMAP family
is "clocksource=", used to override kernel clocksource.

So this patch changes "gp timer" => "gp_timer", for clockevent,
clocksource and timer irq_handler.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>