freedreno/registers: teach gen_header.py about a3xx_regid

This is a builtin type (treated as uint, but with special type-aware
decoding) in envytools/cffdump.  Lets teach gen_header.py about it and
drop the enum hack in the xml so I don't have to keep deleting the enum
when I sync the xml back to the freedreno envytools tree.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3833>

src/freedreno/registers/adreno_common.xml

@@ -280,10 +280,6 @@ xsi:schemaLocation="http://nouveau.freedesktop.org/ rules-ng.xsd">
 	Common between A3xx and A4xx:
  -->
 
-<enum name="a3xx_regid">
-  <value name="REGID_UNUSED" value="0xfc"/>
-</enum>
-
 <enum name="a3xx_rop_code">
 	<value name="ROP_CLEAR"         value="0"/>
 	<value name="ROP_NOR"           value="1"/>

src/freedreno/registers/gen_header.py

@@ -39,7 +39,7 @@ class Field(object):
 		self.shr = shr
 		self.type = type
 
-		builtin_types = [ None, "boolean", "uint", "hex", "int", "fixed", "ufixed", "float", "address", "waddress" ]
+		builtin_types = [ None, "a3xx_regid", "boolean", "uint", "hex", "int", "fixed", "ufixed", "float", "address", "waddress" ]
 
 		if low < 0 or low > 31:
 			raise parser.error("low attribute out of range: %d" % low)
@@ -61,7 +61,7 @@ class Field(object):
 		elif self.type == "boolean":
 			type = "bool"
 			val = var_name
-		elif self.type == "uint" or self.type == "hex":
+		elif self.type == "uint" or self.type == "hex" or self.type == "a3xx_regid":
 			type = "uint32_t"
 			val = var_name
 		elif self.type == "int":