LibEDID: Do not check if ${PNP_IDS_EXPORT_PATH} exists in pnp_ids.cmake

This check isn't needed because download_file() will check if it exists
already before doing the download. Worse, it would prevent the generator
target from being defined if the file existed, which then made CMake not
realize the generated files were important and delete them.

Meta/CMake/pnp_ids.cmake

@@ -5,7 +5,7 @@ set(PNP_IDS_URL http://www.uefi.org/uefi-pnp-export)
 set(PNP_IDS_EXPORT_PATH ${CMAKE_BINARY_DIR}/pnp_ids.html)
 set(PNP_IDS_INSTALL_PATH ${CMAKE_INSTALL_DATAROOTDIR}/${PNP_IDS_FILE})
 
-if(ENABLE_PNP_IDS_DOWNLOAD AND NOT EXISTS ${PNP_IDS_EXPORT_PATH})
+if (ENABLE_PNP_IDS_DOWNLOAD)
     file(MAKE_DIRECTORY ${CMAKE_INSTALL_DATAROOTDIR})
     download_file("${PNP_IDS_URL}" "${PNP_IDS_EXPORT_PATH}")