build: restore opkg-related provides logic

build: restore opkg-related provides logic

Re-add opkg provides logic to CONTROL when USE_APK is not set and remove
virtual provider prefix.

Fixes: cefbf11 ("build: refactor provides logic")
Fixes: https://github.com/openwrt/openwrt/issues/21372
Fixes: https://github.com/openwrt/openwrt/issues/21382
Fixes: https://github.com/openwrt/openwrt/issues/21402
Signed-off-by: George Sapkin <george@sapk.in>
Link: https://github.com/openwrt/openwrt/pull/21409
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>