ANDROID: kleaf: get_gki_modules_list add i386 option

Adds "i386" as an option to get the list of 32-bit x86
modules in get_gki_modules_list().

virtual_device_i686 Cuttlefish target is a consumer.
Option is named i386 to match the `arch` attributes
in kernel_build rule.

Bug: 293529933
Test: TH
Change-Id: Ic5278aa687999a2bb2d98b97b204b99d1fcd809a
Signed-off-by: Ramji Jiyani <ramjiyani@google.com>