docs: Mention both "initramfs" and "ramdisk" as available actions

doc/genkernel.8.txt

@@ -50,10 +50,12 @@ actions are supported:
     Build all steps - the kernel, modules, and the ramdisk.
 *bzImage*::
     Build only the kernel.
+*initramfs*::
+    Build only the ramdisk/initramfs.
 *kernel*::
     Build only the kernel and the modules.
-*initramfs*::
+*ramdisk*::
-    Build only the ramdisk.
+    Build only the ramdisk/initramfs.
 
 
 OPTIONS

gen_cmdline.sh

@@ -9,6 +9,7 @@ longusage() {
   echo "Available Actions: "
   echo "  all				Build all steps"
   echo "  bzImage			Build only the kernel"
+  echo "  initramfs			Build only the ramdisk/initramfs"
   echo "  kernel			Build only the kernel and modules"
   echo "  ramdisk			Build only the ramdisk/initramfs"
   echo