Replaced a few more 0xffffffff by the appropriate constants.

diff --git a/dlls/kernel/process.c b/dlls/kernel/process.c
index c9949e9..858ad74 100644
--- a/dlls/kernel/process.c
+++ b/dlls/kernel/process.c
@@ -1750,7 +1750,7 @@
                         0, NULL, NULL, &startup, &info ))
     {
         /* Give 30 seconds to the app to come up */
-        if (wait_input_idle( info.hProcess, 30000 ) == 0xFFFFFFFF)
+        if (wait_input_idle( info.hProcess, 30000 ) == WAIT_FAILED)
             WARN("WaitForInputIdle failed: Error %ld\n", GetLastError() );
         ret = 33;
         /* Close off the handles */
@@ -1808,7 +1808,7 @@
                         params->lpEnvAddress, NULL, &startup, &info ))
     {
         /* Give 30 seconds to the app to come up */
-        if (wait_input_idle( info.hProcess, 30000 ) ==  0xFFFFFFFF )
+        if (wait_input_idle( info.hProcess, 30000 ) == WAIT_FAILED)
             WARN("WaitForInputIdle failed: Error %ld\n", GetLastError() );
         hInstance = (HINSTANCE)33;
         /* Close off the handles */