Support EGL_EXT_protected_content in GLConsumer.

When the consumer creates an EGLImage, it must now pass
EGL_PROTECTED_CONTENT_EXT to eglCreateImageKHR for protected buffers to be
mapped onto the GPU.  This allows us to no longer need QCOM specific flags in
a few places (already removed).

Bug: 27536318
Change-Id: I1c49886d2dcbdceaf5fa9a33288753115651b4f2