x86, setup: mark %esi as clobbered in E820 BIOS call

x86, setup: mark %esi as clobbered in E820 BIOS call

upstream commit: 01522df346f846906eaf6ca57148641476209909

Jordan Hargrave diagnosed a BIOS clobbering %esi in the E820 call.
That particular BIOS has been fixed, but there is a possibility that
this is responsible for other occasional reports of early boot
failure, and it does not hurt to add %esi to the clobbers.

-stable candidate patch.

Cc: Justin Forbes <jmforbes@linuxtx.org>
Signed-off-by: Michael K Johnson <johnsonm@rpath.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: stable@kernel.org
Signed-off-by: Chris Wright <chrisw@sous-sol.org>