tools: remove phosphor-ipmi-blobs dependency

The host tool depended on the BMC header: firmware_handler.hpp because
it defined the flags.  This header depends on phosphor-ipmi-blobs,
therefore the host-tool depends on this.  Move the flags into a separate
common header file and snip this dependency.

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: Id2ad33a1611c02605a1ed5c695429d0451eb98d4
diff --git a/flags.hpp b/flags.hpp
new file mode 100644
index 0000000..d7c89d5
--- /dev/null
+++ b/flags.hpp
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <cstdint>
+
+namespace ipmi_flash
+{
+
+class FirmwareFlags
+{
+  public:
+    enum UpdateFlags : std::uint16_t
+    {
+        openRead = (1 << 0),  /* Flag for reading. */
+        openWrite = (1 << 1), /* Flag for writing. */
+        ipmi = (1 << 8), /* Expect to send contents over IPMI BlockTransfer. */
+        p2a = (1 << 9),  /* Expect to send contents over P2A bridge. */
+        lpc = (1 << 10), /* Expect to send contents over LPC bridge. */
+    };
+};
+
+} // namespace ipmi_flash