Fix brcm-egl plugin to compile

wl_brcm was renamed to qt_brcm. Also adapt the brcm-egl
waylandcompositor plugin to use qtwaylandscanner.

Change-Id: Id8539389b7f22b107ba7349f7ba1e7ffa4a59eb1
Reviewed-by: Andy Nichols <andy.nichols@digia.com>