bcm53xx: build a single device per profile

bcm53xx: build a single device per profile

So far every build of a single bcm53xx Target Profile (it means: when
NOT using CONFIG_TARGET_MULTI_PROFILE) resulted in all target devices
images being built. Now it only builds the one matching selected
profile.

Fixes: #13572
Suggested-by: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Rani Hod <rani.hod@gmail.com>
[rmilecki: update commit subject + body & move PROFILES line]
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
(cherry picked from commit 802a5f5cb4a7b42d25e82b787d7ab1323a20183f)