automake: move GALLIUM_DRI_LIB_DEPS to Automake.inc

automake: move GALLIUM_DRI_LIB_DEPS to Automake.inc

With recent commit we started de-duplicating all of the compiler/
linker flags moving their handling inside Automake.inc.

This did not take into consideration that the above variable was set
at configure time, leading to issues on certain build combinations.

Move the variable to where it's used/handled thus cleaning up
configure.ac.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76848
Tested-by: Vinson Lee <vlee@freedesktop.org>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>