Merge pull request #2171 from Gelbpunkt/acpi-smp-x86

fix: Enable ACPI for SMP on x86_64

Author: mkroening

Cargo.toml

@@ -54,7 +54,7 @@ pci = ["virtio?/pci"]
 rtl8139 = ["net", "pci", "volatile/derive", "endian-num"]
 semihosting = ["dep:semihosting"]
 shell = ["simple-shell"]
-smp = []
+smp = ["acpi"] # on x86_64, SMP only works together with ACPI
 strace = []
 tcp = ["net", "smoltcp", "smoltcp/socket-tcp"]
 trace = ["smoltcp?/log", "smoltcp?/verbose"]