compiler: Rename INTERP_QUALIFIER_* to INTERP_MODE_*.

Likewise, rename the enum type to glsl_interp_mode.

Beyond the GLSL front-end, talking about "interpolation modes" seems
more natural than "interpolation qualifiers" - in the IR, we're removed
from how exactly the source language specifies how to interpolate an
input.  Also, SPIR-V calls these "decorations" rather than "qualifiers".

Generated by:
$ find . -regextype egrep -regex '.*\.(c|cpp|h)' -type f -exec sed -i \
  -e 's/INTERP_QUALIFIER_/INTERP_MODE_/g' \
  -e 's/glsl_interp_qualifier/glsl_interp_mode/g' {} \;

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Acked-by: Dave Airlie <airlied@redhat.com>

src/compiler/glsl/ir.h

@@ -592,7 +592,7 @@ public:
 
    inline bool is_interpolation_flat() const
    {
-      return this->data.interpolation == INTERP_QUALIFIER_FLAT ||
+      return this->data.interpolation == INTERP_MODE_FLAT ||
              this->type->contains_integer() ||
              this->type->contains_double();
    }
@@ -686,7 +686,7 @@ public:
       /**
        * Interpolation mode for shader inputs / outputs
        *
-       * \sa glsl_interp_qualifier
+       * \sa glsl_interp_mode
        */
       unsigned interpolation:2;