rk3399: bl31: update version to 1.15

Build from ATF commit:
    d98d16e plat: rk3399: suspend: remove ddr debug log in suspend and dfs
update feature:
    d98d16e plat: rk3399: suspend: remove ddr debug log in suspend and dfs
    c4e7b9a plat: rk3399: suspend: support only one channel
    824db84 rockchip: disable uart fiq when cpu/systerm resume

Change-Id: Ic2f4cd81bea778d1a107c5b1842f5b9f4140d5e2
Signed-off-by: XiaoDong Huang <derrick.huang@rock-chips.com>

RKTRUST/RK3399TRUST.ini

@@ -5,7 +5,7 @@ MINOR=0
 SEC=0
 [BL31_OPTION]
 SEC=1
-PATH=tools/rk_tools/bin/rk33/rk3399_bl31_v1.14.elf
+PATH=tools/rk_tools/bin/rk33/rk3399_bl31_v1.15.elf
 ADDR=0x00010000
 [BL32_OPTION]
 SEC=1