Add .discinfo on all arches

It was previously added to s390x and ppc64le, this adds it for aarch64,
ppc, and x86 images.

Resolves: rhbz#2030008

80-rhel/aarch64.tmpl

@@ -78,6 +78,7 @@ mkdir ${KERNELDIR}
 runcmd xorrisofs ${isoargs} -o ${outroot}/images/boot.iso \
        ${efiargs} -R -J -V '${isolabel}' \
        -graft-points \
+       .discinfo=${outroot}/.discinfo \
        ${KERNELDIR}=${outroot}/${KERNELDIR} \
        ${STAGE2IMG}=${outroot}/${STAGE2IMG} \
        ${efigraft} ${filegraft}

80-rhel/ppc.tmpl

@@ -107,6 +107,7 @@ runcmd mkisofs -o ${outroot}/images/boot.iso -chrp-boot -U \
         -hfs-volid ${product.version} -hfs-bless ${outroot}/${MACDIR} \
         -map ${inroot}/${configdir}/mapping \
         -no-desktop -allow-multidot ${udfargs} -graft-points \
+        .discinfo=${outroot}/.discinfo \
         ${BOOTDIR}=${outroot}/${BOOTDIR} \
         ${GRUBDIR}=${outroot}/${GRUBDIR} \
         ${STAGE2IMG}=${outroot}/${STAGE2IMG} ${filegraft}

80-rhel/x86.tmpl

@@ -127,6 +127,7 @@ runcmd xorrisofs ${isoargs} -o ${outroot}/images/boot.iso \
        -boot-load-size 4 -boot-info-table -no-emul-boot \
        ${efiargs} -R -J -V '${isolabel}' \
        -graft-points \
+       .discinfo=${outroot}/.discinfo \
        ${STAGE2IMG}=${outroot}/${STAGE2IMG} \
        ${BOOTDIR}=${outroot}/${BOOTDIR} \
        ${KERNELDIR}=${outroot}/${KERNELDIR} \