hyperv/utils: Allow hint to disable individual utility

[decui_microsoft.com]

LGTM

[kib]

sys/dev/hyperv/utilities/hv_heartbeat.c

98

Might be, use more structural names, like hyperv.heartbeat etc ?

99

Note that style requires braces () around the return value.

[sepherosa_gmail.com]

sys/dev/hyperv/utilities/hv_heartbeat.c

98

Not 100% sure about the practice, but looks like most users of resource_disabled() just use the driver's name

99

Hmm, this tries to make the style consistent within this function :)