omap2plus_defconfig is missing CONFIG_ARCH_MULTI_V6. This results in
undefined instruction traps in u-boot (and boot failures) on OMAP2xxx
SoCs, which are ARM11-based. Fix by setting CONFIG_ARCH_MULTI_V6.
Signed-off-by: Paul Walmsley <paul@pwsan.com> Signed-off-by: Tony Lindgren <tony@atomide.com>