xf86drm: fix return type for drmIsMaster()

Xserver has struct members named `bool`, which means the last commit
breaks its build with errors like this:

  error: two or more data types in declaration specifiers
  Bool bool;
       ^

Fix this by making it return a 0/1 integer, with the same semantic as
the boolean it was before.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=109587
Fixes: 17dfe3ac93 "xf86drm: Add drmIsMaster()"
Cc: Christopher James Halse Rogers <christopher.halse.rogers@canonical.com>
Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

xf86drm.c

@@ -2743,7 +2743,7 @@ drm_public int drmDropMaster(int fd)
         return drmIoctl(fd, DRM_IOCTL_DROP_MASTER, NULL);
 }
 
-drm_public bool drmIsMaster(int fd)
+drm_public int drmIsMaster(int fd)
 {
         /* Detect master by attempting something that requires master.
          *

xf86drm.h

@@ -37,7 +37,6 @@
 #include <stdarg.h>
 #include <sys/types.h>
 #include <stdint.h>
-#include <stdbool.h>
 #include <drm.h>
 
 #if defined(__cplusplus)
@@ -734,7 +733,7 @@ extern void drmMsg(const char *format, ...) DRM_PRINTFLIKE(1, 2);
 
 extern int drmSetMaster(int fd);
 extern int drmDropMaster(int fd);
-extern bool drmIsMaster(int fd);
+extern int drmIsMaster(int fd);
 
 #define DRM_EVENT_CONTEXT_VERSION 4