hwstub: port hwstub_shell to the new library

Also use this opportunity to cleanup support for multiple devices: the shell
now supports dynamic changes in the device and will call init() everytime
a new device is selected, to prepare a new environment. The shell now
honors register width on register read/write. The shell also provides access
to variants as follows by creating a subtable under the register using the
variant type in UPPER case and having the same layout as a register.
For example if register HW.GPIO.DIR has variants "set" and "clr", those can
be used like this:
HW.GPIO.DIR.SET.write(0xff)
HW.GPIO.DIR.CLR.write(0xff00)

Change-Id: I943947fa98bce875de0cba4338e8b7196a4c1165

utils/hwstub/tools/lua/jz.lua

@@ -0,0 +1,26 @@
+---
+--- Chip Identification
+---
+JZ = { info = {} }
+
+local h = HELP:create_topic("JZ")
+h:add("This table contains the abstraction of the different device blocks for the JZ.")
+h:add("It allows one to use higher-level primitives rather than poking at register directly.")
+
+hh = h:create_topic("debug")
+hh:add("STMP.debug(...) prints some debug output if JZ.debug_on is true and does nothing otherwise.")
+
+JZ.debug_on = false
+
+function STMP.debug(...)
+    if STMP.debug_on then print(...) end
+end
+
+-- init
+function JZ.init()
+    local desc = string.format("jz%04x%c", hwstub.dev.jz.chipid, hwstub.dev.jz.rev)
+    desc = desc:lower()
+    if not hwstub.soc:select(desc) then
+        print("Looking for soc " .. desc .. ": not found. Please load a soc by hand.")
+    end
+end