gnu: Use new ovmf firmware packages.

* doc/guix.texi (Invoking guix system): Update qemu command to use
ovmf-x86-64.
* gnu/packages/virtualization.scm (xen)[inputs]: Replace ovmf with
ovmf-i686.
* gnu/tests/install.scm (uefi-firmware): Use system appropriate ovmf
firmware.

Change-Id: Ia2ff76eaf766c8d4fb0be4a7cc7b8941574433d0

doc/guix.texi

@@ -42580,7 +42580,7 @@ image=$(guix system image --image-type=qcow2 \
 cp $image /tmp/my-image.qcow2
 chmod +w /tmp/my-image.qcow2
 qemu-system-x86_64 -enable-kvm -hda /tmp/my-image.qcow2 -m 1000 \
-                   -bios $(guix build ovmf)/share/firmware/ovmf_x64.bin
+                   -bios $(guix build ovmf-x86-64)/share/firmware/ovmf_x64.bin
 @end example
 
 When using the @code{mbr-hybrid-raw} image type, a raw disk image is

gnu/packages/virtualization.scm

@@ -2670,7 +2670,7 @@ (define (filter-environment! filter-predicate
            yajl
            ncurses
            openssl
-           ovmf
+           ovmf-i686
            pixman
            qemu-minimal
            seabios

gnu/tests/install.scm

@@ -210,9 +210,9 @@ (define (uefi-firmware system)
   "Return the appropriate QEMU OVMF UEFI firmware for the given SYSTEM."
   (cond
    ((string-prefix? "x86_64" system)
-    (file-append ovmf "/share/firmware/ovmf_x64.bin"))
+    (file-append ovmf-x86-64 "/share/firmware/ovmf_x64.bin"))
    ((string-prefix? "i686" system)
-    (file-append ovmf "/share/firmware/ovmf_ia32.bin"))
+    (file-append ovmf-i686 "/share/firmware/ovmf_ia32.bin"))
    (else #f)))
 
 (define* (run-install target-os target-os-source