maint: Tweak release manifest special case for armhf-linux.

Don't remove the emacs package, as it does build and substitutes are
available. Do remove the guix package though, as it doesn't build due to Guile
memory issues while compiling the package modules.

* etc/release-manifest.scm (%base-packages/armhf): Don't replace the emacs
package, remove the guix package.
(%base-manifest): Remove FIXME comment as %base-packages/armhf doesn't relate
to build power.

etc/release-manifest.scm

@@ -51,12 +51,11 @@ TARGET."
          "openssh" "emacs" "vim" "python" "guile" "guix")))
 
 (define %base-packages/armhf
-  ;; XXX: Relax requirements for armhf-linux for lack of enough build power.
-  (map (lambda (package)
-         (if (string=? (package-name package) "emacs")
-             (specification->package "emacs-no-x")
-             package))
-       %base-packages))
+  ;; The guix package doesn't build natively on armhf due to Guile memory
+  ;; issues compiling the package modules
+  (remove (lambda (package)
+            (string=? (package-name package) "guix"))
+          %base-packages))
 
 (define %base-packages/hurd
   ;; XXX: For now we are less demanding of "i586-gnu".
@@ -112,8 +111,6 @@ TARGET."
                       (cond ((string=? system "i586-gnu")
                              %base-packages/hurd)
                             ((string=? system "armhf-linux")
-                             ;; FIXME: Drop special case when ci.guix.gnu.org
-                             ;; has more ARMv7 build power.
                              %base-packages/armhf)
                             ((string=? system "powerpc64le-linux")
                              ;; FIXME: Drop 'bootstrap-tarballs' until