platform: msm_shared: Make the SSD Image decrypt SCM call atomic

Make an atomic SCM call for SSD Image decryption so that IRQs are disabled
until the scm call is returned.

Change-Id: I62502a6af2afb384beae2b8258f3c1e34ef30541
diff --git a/platform/msm_shared/scm.c b/platform/msm_shared/scm.c
index ff403b8..6042fab 100644
--- a/platform/msm_shared/scm.c
+++ b/platform/msm_shared/scm.c
@@ -424,6 +424,7 @@
 			scm_arg.x1 = MAKE_SCM_ARGS(0x2,SMC_PARAM_TYPE_VALUE,SMC_PARAM_TYPE_BUFFER_READWRITE);
 			scm_arg.x2 = parse_req.md_len;
 			scm_arg.x3 = (uint32_t) parse_req.md;
+			scm_arg.atomic = true;
 
 			ret = scm_call2(&scm_arg, &scm_ret);
 			parse_rsp.status = scm_ret.x1;