gpu: Fix a syntax error in X86GPUTLB.py.

The recent changes which removed master/slave terminology also
accidentally deleted an "=", making the syntax in that file illegal.

Change-Id: I50aa945f0f66765db36775380b98a88caff23c13
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/34576
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>

src/gpu-compute/X86GPUTLB.py

@@ -77,6 +77,6 @@ class TLBCoalescer(ClockedObject):
     slave    = DeprecatedParam(cpu_side_ports,
                         '`slave` is now called `cpu_side_ports`')
     mem_side_ports = VectorRequestPort("Port on side closer to memory")
-    master   DeprecatedParam(mem_side_ports,
+    master   = DeprecatedParam(mem_side_ports,
                         '`master` is now called `mem_side_ports`')
     disableCoalescing = Param.Bool(False,"Dispable Coalescing")