include/ec_commands.h: Move extern "C" after headers
include/ec_commands.h: Move extern "C" after headers

The headers that ec_commands.h include have C++ templates in them, which
must have C++ linkage when using C++:

/usr/bin/../include/c++/v1/cstddef:56:1: error: templates must have C++
linkage

BRANCH=none
BUG=b:144959033
TEST=make buildall

Signed-off-by: Tom Hughes <fc5c12f30a5ed2baa0581f44ee14ad1eb7b20d83@chromium.org>
Change-Id: Ic535d90fa7861ac291c85f6c26dda4368c7b4ee9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2869428
Reviewed-by: Denis Brockus <6b21e8190fb5e373363fb95271367073a16474ef@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec