Revert "cmake: rpi videocore needs brcmegl as well"
This reverts commit cd313811850c4f474ee5dec7bd1842e2cb4c2043.
Linking libbrcmEGL.so explicitly breaks (causes segmentation faults) in other code that links and runs the X11 EGL.
Reopens https://github.com/libsdl-org/SDL/issues/14749
At least in my Raspbian Stretch build environment, the vc_dispmanx symbols that were missing are found in libbcm_host.so, which is linked by default.
(cherry picked from commit 7fe30b04bf0f92e3776680c629296634085f7df8)