securemsm-kernel: qseecom: remove ion.h header include

ion is deprecated now. Removing header as it is no longer
needed.

Test:
Tested compilation on sun and pineapple builds.

Change-Id: Ic67d389b7161e7c1daade147a719140456156ca3
Signed-off-by: Anmolpreet Kaur <[email protected]>

qseecom/qseecom.c

@@ -22,7 +22,6 @@
 #include <linux/mutex.h>
 #include <linux/io.h>
 #include <linux/dma-buf.h>
-#include <linux/ion.h>
 #include <linux/msm_ion.h>
 #include <linux/types.h>
 #include <linux/clk.h>