arm64: don't loop forever if first option in kern.cfg.order not available

[imp]

Summary

strchr returns a pointer to the ',', so if the first option in the list
isn't available, we need to step over the , to look at the next
option. So if kern.cfg.order="acpi,fdt" and we have no acpi, we'd loop
forever with order=',fdt'.

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[jhb]

typo in the title: s/forver/forever/

Not sure if you want to quote the comma in the second line, or maybe just spell it out (e.g. "we need to step over the comma")

[imp]

In D36682#832825, @jhb wrote:

Not sure if you want to quote the comma in the second line, or maybe just spell it out (e.g. "we need to step over the comma")

Will add before push. Thanks!

[jrtc27]

Ah yes I remember this issue