ARM: omap3: evm: Enable CONFIG_BLK and misc. cleanup

ARM: omap3: evm: Enable CONFIG_BLK and misc. cleanup

This commit enables CONFIG_BLK and removes USB_STORAGE which is awaiting
proper implementation for current U-Boot interfaces. Additionally the
console selection is now handled by Kconfig and no longer needs to be in
the config header. CONFIG_SYS_MALLOC_F_LEN=0x2000 was added to sync with
other boards. CONFIG_SPL_BLK and CONFIG_SPL_DM_MMC are disabled because
they currently do not allow the OMAP3-EVM (OMAP34XX) to actually boot.

Signed-off-by: Derald D. Woods <woods.technical@gmail.com>