keymaps: fr-ca: add missing keys

Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 20170712072305.29233-1-kraxel@redhat.com

pc-bios/keymaps/fr-ca

@@ -48,3 +48,5 @@ parenleft 0xa shift
 parenright 0xb shift
 underscore 0xc shift
 plus 0xd shift
+minus 0xc
+equal 0xd