ARM: OMAP4: clock: Add missing clock divider for OCP_ABE_ICLK

ARM: OMAP4: clock: Add missing clock divider for OCP_ABE_ICLK

The parent clock of the OCP_ABE_ICLK is the AESS_FCLK and the
parent clock of the AESS_FCLK is the ABE_FCLK...

ABE_FCLK --> AESS_FCLK --> OCP_ABE_ICLK

The AESS_FCLK and OCP_ABE_ICLK clocks both have dividers which
determine their operational frequency. However, the dividers for
the AESS_FCLK and OCP_ABE_ICLK are controlled via a single bit,
which is the CM1_ABE_AESS_CLKCTRL[24] bit. When this bit is set to
0, the AESS_FCLK divider is 1 and the OCP_ABE_ICLK divider is 2.
Similarly, when this bit is set to 1, the AESS_FCLK divider is 2
and the OCP_ABE_ICLK is 1.

The above relationship between the AESS_FCLK and OCP_ABE_ICLK
dividers ensure that the OCP_ABE_ICLK clock is always half the
frequency of the ABE_CLK...

OCP_ABE_ICLK = ABE_FCLK/2

The divider for the OCP_ABE_ICLK is currently missing so add a
divider that will ensure the OCP_ABE_ICLK frequency is always half
the ABE_FCLK frequency.

Signed-off-by: Jon Hunter <jon-hunter@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>