Revert omap34xx_sram_init() rename to sync with mainline

Looks like the only chunk not merged to mainline out of patch
19a62998e238b094e63644393a599edb6c0b13c8 is the rename of
omap34xx_sram_init() to omap3_sram_init(). Revert it for
now to get the code in sync with mainline. It can be renamed
later on if there's need for it.

Signed-off-by: Tony Lindgren <tony@atomide.com>