build: Remove the exposed "cmos" feature

This only affects the build system; the feature was already always
compiled in with ca68b9e7a9

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

vmm/Cargo.toml

@@ -6,7 +6,6 @@ edition = "2021"
 
 [features]
 default = []
-cmos = ["devices/cmos"]
 fwdebug = ["devices/fwdebug"]
 gdb = ["kvm", "gdbstub", "gdbstub_arch"]
 guest_debug = ["kvm"]