configure.ac: check require_basic_egl only if egl enabled

Otherwise the configuration fails when building independant libs
like vdpau, vaapi or omx

Fixes: 1ac40173c2a ("configure.ac: simplify EGL requirements for
drivers dependent on EGL")

Signed-off-by: Leo Liu <leo.liu@amd.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Cc: "17.0" <mesa-stable@lists.freedesktop.org>
(cherry picked from commit 5398d006de3d2bd668e3fc4b80a3de0c101a3e43)
[Emil Velikov: resolve trivial conflicts]
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>

Conflicts:
	configure.ac
1 file changed