kconfig: split CONFIG_SPARSE_MEM from fuzzing

Pass CONFIG_FUZZ via host_kconfig, and use it to select the
sparse-mem device.

Cc: Alexander Oleinik <alxndr@bu.edu>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20211007130829.632254-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Kconfig.host

@@ -41,3 +41,7 @@ config PVRDMA
 config MULTIPROCESS_ALLOWED
     bool
     imply MULTIPROCESS
+
+config FUZZ
+    bool
+    select SPARSE_MEM

hw/mem/Kconfig

@@ -8,3 +8,6 @@ config MEM_DEVICE
 config NVDIMM
     bool
     select MEM_DEVICE
+
+config SPARSE_MEM
+    bool

hw/mem/meson.build

@@ -6,4 +6,4 @@ mem_ss.add(when: 'CONFIG_NVDIMM', if_true: files('nvdimm.c'))
 
 softmmu_ss.add_all(when: 'CONFIG_MEM_DEVICE', if_true: mem_ss)
 
-softmmu_ss.add(when: 'CONFIG_FUZZ', if_true: files('sparse-mem.c'))
+softmmu_ss.add(when: 'CONFIG_SPARSE_MEM', if_true: files('sparse-mem.c'))

meson.build

@@ -1599,6 +1599,7 @@ endif
 
 have_ivshmem = config_host_data.get('CONFIG_EVENTFD')
 host_kconfig = \
+  ('CONFIG_FUZZ' in config_host ? ['CONFIG_FUZZ=y'] : []) + \
   ('CONFIG_TPM' in config_host ? ['CONFIG_TPM=y'] : []) + \
   ('CONFIG_SPICE' in config_host ? ['CONFIG_SPICE=y'] : []) + \
   (have_ivshmem ? ['CONFIG_IVSHMEM=y'] : []) + \