imx-gpu-viv: fix build with libvulkan

imx-gpu-viv: fix build with libvulkan

vulkan-loader and imx-gpu-viv both provide a libvulkan.so with the same soname.
(The vulkan-loader provides the vulkan-loader while imx-gpu-viv provides the
instalable client driver for the Vivante GPU).

  readelf -a .../recipe-sysroot/usr/lib/libvulkan.so | grep soname
    0x000000000000000e (SONAME)             Library soname: [libvulkan.so.1]
  readelf -a .../recipe-sysroot/usr/lib/vulkan/libvulkan_VSI.so | grep soname
    0x000000000000000e (SONAME)             Library soname: [libvulkan.so.1]

This leads to the following build error.

| # ERROR: gstreamer1.0-plugins-bad-1.14.imx-r0 do_package: gstreamer1.0-plugins-bad-vulkan: Multiple shlib providers for libvulkan.so.1: libvulkan-imx, vulkan-loader (used by files: ...libgstvulkan.so)
| # ERROR: gstreamer1.0-plugins-bad-1.14.imx-r0 do_package_qa: QA Issue: /usr/lib/gstreamer-1.0/libgstvulkan.so contained in package gstreamer1.0-plugins-bad-vulkan requires libvulkan.so.1()(64bit), but no providers found in RDEPENDS_gstreamer1.0-plugins-bad-vulkan? [filed]

Fix this by changing the soname of the Vivante provided libvulkan.
With this change we can drop the /usr/lib/vulkan install directory and
install directly in /usr/lib/.
This additionally allows to reenable QA warnings for the libvulkan-imx package.

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>