qapi/machine: Drop temporary 'prefix'

Recent commit "qapi: Smarter camel_to_upper() to reduce need for
'prefix'" added a temporary 'prefix' to delay changing the generated
code.

Revert it.  This improves HmatLBDataType's generated enumeration
constant prefix from HMATLB_DATA_TYPE to HMAT_LB_DATA_TYPE, and
HmatLBMemoryHierarchy's from HMATLB_MEMORY_HIERARCHY to
HMAT_LB_MEMORY_HIERARCHY.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Message-ID: <20240904111836.3273842-8-armbru@redhat.com>

qapi/machine.json

@@ -686,7 +686,6 @@
 # Since: 5.0
 ##
 { 'enum': 'HmatLBMemoryHierarchy',
-  'prefix': 'HMATLB_MEMORY_HIERARCHY', # TODO drop
   'data': [ 'memory', 'first-level', 'second-level', 'third-level' ] }
 
 ##
@@ -713,7 +712,6 @@
 # Since: 5.0
 ##
 { 'enum': 'HmatLBDataType',
-  'prefix': 'HMATLB_DATA_TYPE', # TODO drop
   'data': [ 'access-latency', 'read-latency', 'write-latency',
             'access-bandwidth', 'read-bandwidth', 'write-bandwidth' ] }