SurfaceFlinger: Make secure display ifdefs more narrow.

  * apq8084 target hals do not export display attrs
   the same as previous platforms (8974, 8960 etc)
   but continue the use of QCOM_BSP.
  * Due to this difference secure content is non-visible
   on apq8084 platforms because SF pushes the rendering
   to GLES vice the secure buffer of HWC and MDP.

Change-Id: Ie078638b1e22d1c9f73441e290c2882b4081b294
libEGL: allow devices to workaround Google bug 10194508

Most older blobs don't have the EGL_KHR_gl_colorspace
extension and need this workaround.

Change-Id: Ifc5d097c1a0b68275d23c2d191976ac96631b695
opengl: reduce PB size from 2MB to 512KB

this allows us to enable h/w acceleration on low-end
devices while keeping memory usage down.

Bug: 6557760
Change-Id: I8af2de3038dc2579360b8b73aa452cb7a0e506a9