[resend with minor build fix and updated description]

Follow the lead of the TI kernels by removing PRCM #2 and adding PRCM
#3 and #4 to the rate-table entries.  According to TI, having #2 and
#3 together is known to be a bad combination.

Also, change the default divider values for the PRCM #5a setting to
match those of the TI kernel.  Using the smallest divider possible can
give significant power savings when using the data-driven idle modes.
Signed-off-by: Kevin Hilman <khilman@mvista.com>
Acked-by: Richard Woodruff <r-woodruff2@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>