meta: add PERF_EVENTS config to uprobes feature

CONFIG_UPROBES depends on CONFIG_PERF_EVENTS being set, so PERF_EVENTS
needs to be added whenever uprobes are enabled.

Signed-off-by: Tom Zanussi <tom.zanussi@intel.com>

features/uprobe/uprobe.cfg

 CONFIG_UPROBES=y
 CONFIG_UPROBE_EVENT=y
+CONFIG_PERF_EVENTS=y