omap4: Remove 'FIXME: omap44xx_sram_init not implemented'

omap4: Remove 'FIXME: omap44xx_sram_init not implemented'

The omap44xx_sram_init() implements functionality to push some
code on SRAM whenever the code can't be executed from external
memory. The low power and DVFS code can be executed from
external DDR itself thanks to OMAP4  memory controller hardware
support. So on OMAP4, sram_push kind of functionality isn't needed.

Hence remove the FIXME warning added for implementing sram push
feature on OMAP4.

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>