Currently U-Boot on x86 only supports chromebook-x86 build, and is booting from
coreboot which initializes things like DRAM and processor/chipset specific low
level stuff.

There is an option CONFIG_X86_RESET_VECTOR to include the x86 reset vector and
the 16-bit real mode codes for building a ROM version of U-Boot, however that
build is broken due to the linking process misses resetvec.o and start16.o

This checkin fixes the U-Boot x86 build when CONFIG_X86_RESET_VECTOR is on.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>