S7: PXP Bringup Bootloader BL30 code portinig [2/3]

PD#SWPL-131338

Problem:
S7 PXP Bringup Bootloader BL30.

Solution:
Code porting from s4

Verify:
Test in S7 PXP.

Change-Id: I34d00f144cf1dcf92dca31f1726a0dd8a57afbdd
Signed-off-by: bangzheng.liu <bangzheng.liu@amlogic.com>
diff --git a/build_combination.in b/build_combination.in
index 88b7ca7..c15ac22 100644
--- a/build_combination.in
+++ b/build_combination.in
@@ -19,3 +19,4 @@
 riscv s5 ax201_s928x aocpu
 riscv s5 ax208_s928x aocpu
 riscv s5 ax209_s928x aocpu
+riscv s7 s7_skt aocpu