arch/x86: rename reset_vector -> _start

In order to align the entry points for the various stages
on x86 to _start one needs to rename the reset_vector symbol.
The section is the same; it's just a symbol change.

Change-Id: I0e6bbf1da04a6e248781a9c222a146725c34268a
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/13881
Tested-by: build bot (Jenkins)
Reviewed-by: Andrey Petrov <andrey.petrov@intel.com>
3 files changed