gnu: Remove packages deprecated for over a year.

* gnu/packages/admin.scm (intel-gpu-tools): Remove variable.
* gnu/packages/algebra.scm (giac-xcas): Likewise.

gnu/packages/admin.scm

@@ -2880,9 +2880,6 @@ Intel DRM Driver.")
     (supported-systems '("i686-linux" "x86_64-linux"))
     (license license:expat)))
 
-(define-public intel-gpu-tools
-  (deprecated-package "intel-gpu-tools" igt-gpu-tools))
-
 (define-public fabric
   (package
     (name "fabric")

gnu/packages/algebra.scm

@@ -432,9 +432,6 @@ maple, mupad and the TI89.  It is available as a standalone program (graphic
 or text interfaces) or as a C++ library.")
     (license license:gpl3+)))
 
-(define-public giac-xcas
-  (deprecated-package "giac-xcas" giac))
-
 (define-public flint
   (package
    (name "flint")