util/xcompile/xcompile: Add a space before `&&`

Change-Id: I07fd4d6f6db220e23da8daced6014ce39894c604
Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-on: https://review.coreboot.org/17159
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
1 file changed