get rid of generic instances of asm/exec.h

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/c6x/include/asm/Kbuild b/arch/c6x/include/asm/Kbuild
index 3af601e..e59c9f0 100644
--- a/arch/c6x/include/asm/Kbuild
+++ b/arch/c6x/include/asm/Kbuild
@@ -11,6 +11,7 @@
 generic-y += dma.h
 generic-y += emergency-restart.h
 generic-y += errno.h
+generic-y += exec.h
 generic-y += fb.h
 generic-y += fcntl.h
 generic-y += futex.h