ARM: 6375/1: plat-nomadik: MTU timer trivial bug fix

timer0 to 3 are all on mtu block 0, so don't calculate the clock event
rate based upon mtu block 1's clock speed.

Acked-by: Alessandro Rubini <rubini@unipv.it>
Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>