x86/livepatch: Fail the build if duplicate symbols exist

x86/livepatch: Fail the build if duplicate symbols exist

The binary diffing algorithm used by xen-livepatch depends on having unique
symbols.

The livepatch loading algorithm used by Xen resolves relocations by symbol
name, and thus also depends on having unique symbols.

Introduce CONFIG_ENFORCE_UNIQUE_SYMBOLS to control failing the build if
duplicate symbols are found, and disable it in the RANDCONFIG build.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Release-acked-by: Juergen Gross <jgross@suse.com>