kconfig: introduce kconfig files

The Kconfig files were generated mostly with this script:

  for i in `grep -ho CONFIG_[A-Z0-9_]* default-configs/* | sort -u`; do
    set fnord `git grep -lw $i -- 'hw/*/Makefile.objs' `
    shift
    if test $# = 1; then
      cat >> $(dirname $1)/Kconfig << EOF
config ${i#CONFIG_}
    bool

EOF
      git add $(dirname $1)/Kconfig
    else
      echo $i $*
    fi
  done
  sed -i '$d' hw/*/Kconfig
  for i in hw/*; do
    if test -d $i && ! test -f $i/Kconfig; then
      touch $i/Kconfig
      git add $i/Kconfig
    fi
  done

Whenever a symbol is referenced from multiple subdirectories, the
script prints the list of directories that reference the symbol.
These symbols have to be added manually to the Kconfig files.

Kconfig.host and hw/Kconfig were created manually.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Message-Id: <20190123065618.3520-27-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/display/Kconfig

@@ -0,0 +1,77 @@
+config EDID
+    bool
+
+config FW_CFG_DMA
+    bool
+
+config ADS7846
+    bool
+
+config VGA_CIRRUS
+    bool
+
+config G364FB
+    bool
+
+config JAZZ_LED
+    bool
+
+config PL110
+    bool
+
+config SII9022
+    bool
+
+config SSD0303
+    bool
+
+config SSD0323
+    bool
+
+config VGA_PCI
+    bool
+
+config VGA_ISA
+    bool
+
+config VGA_ISA_MM
+    bool
+
+config VMWARE_VGA
+    bool
+
+config BOCHS_DISPLAY
+    bool
+
+config BLIZZARD
+    bool
+
+config FRAMEBUFFER
+    bool
+
+config MILKYMIST_TMU2
+    bool
+
+config SM501
+    bool
+
+config TCX
+    bool
+
+config CG3
+    bool
+
+config VGA
+    bool
+
+config QXL
+    bool
+
+config VIRTIO_GPU
+    bool
+
+config VIRTIO_VGA
+    bool
+
+config DPCD
+    bool