riscv-softmmu.mak: replace CONFIG_* with Kconfig "select" directives

%-softmmu.mak only keep boards and optional device
definitions in Kconfig mode.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

default-configs/riscv32-softmmu.mak

-# Default configuration for riscv-softmmu
+# Default configuration for riscv32-softmmu
 
-CONFIG_PCI=y
-CONFIG_PCI_DEVICES=y
-CONFIG_SERIAL=y
-CONFIG_VIRTIO_MMIO=y
-
-CONFIG_CADENCE=y
-
-CONFIG_PCI_EXPRESS=y
-CONFIG_PCI_EXPRESS_GENERIC_BRIDGE=y
-
-CONFIG_VGA=y
-CONFIG_VGA_PCI=y
+# Uncomment the following lines to disable these optional devices:
+#
+#CONFIG_PCI_DEVICES=n
 
+# Boards:
+#
 CONFIG_SPIKE=y
-CONFIG_HART=y
 CONFIG_SIFIVE_E=y
-CONFIG_SIFIVE=y
 CONFIG_SIFIVE_U=y
 CONFIG_RISCV_VIRT=y

default-configs/riscv64-softmmu.mak

-# Default configuration for riscv-softmmu
+# Default configuration for riscv64-softmmu
 
-CONFIG_PCI=y
-CONFIG_PCI_DEVICES=y
-CONFIG_SERIAL=y
-CONFIG_VIRTIO_MMIO=y
-
-CONFIG_CADENCE=y
-
-CONFIG_PCI_EXPRESS=y
-CONFIG_PCI_EXPRESS_GENERIC_BRIDGE=y
-
-CONFIG_VGA=y
-CONFIG_VGA_PCI=y
-
-CONFIG_SPIKE=y
-CONFIG_HART=y
-CONFIG_SIFIVE_E=y
-CONFIG_SIFIVE=y
-CONFIG_SIFIVE_U=y
-CONFIG_RISCV_VIRT=y
+include riscv32-softmmu.mak

hw/riscv/Kconfig

@@ -9,12 +9,25 @@ config SIFIVE
 
 config SIFIVE_E
     bool
+    select HART
+    select SIFIVE
 
 config SIFIVE_U
     bool
+    select CADENCE
+    select HART
+    select SIFIVE
 
 config SPIKE
     bool
+    select HART
+    select HTIF
+    select SIFIVE
 
 config RISCV_VIRT
     bool
+    select HART
+    select SERIAL
+    select VIRTIO_MMIO
+    select PCI_EXPRESS_GENERIC_BRIDGE
+    select SIFIVE