boot/shim: add BR2_PACKAGE_SHIM_ARCH_SUPPORTS
Add BR2_PACKAGE_SHIM_ARCH_SUPPORTS as requested by Thomas Petazzoni in
https://patchwork.ozlabs.org/project/buildroot/patch/20220419121409.2055818-1-fontaine.fabrice@gmail.com
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[Arnout: reorder options according to check-package]
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>