msm: scm: Mark scm_call_atomic*() return value as signed

scm_call_atomic*() can return a negative 32 bit value indicating
an error. Change the function signature to indicate that this is
possible.

Change-Id: I633bb521410f9a07495ec5e73e3a8b0e9adb7af1
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
diff --git a/arch/arm/mach-msm/scm.c b/arch/arm/mach-msm/scm.c
index 19f7290..6794a88 100644
--- a/arch/arm/mach-msm/scm.c
+++ b/arch/arm/mach-msm/scm.c
@@ -282,7 +282,7 @@
  * This shall only be used with commands that are guaranteed to be
  * uninterruptable, atomic and SMP safe.
  */
-u32 scm_call_atomic1(u32 svc, u32 cmd, u32 arg1)
+s32 scm_call_atomic1(u32 svc, u32 cmd, u32 arg1)
 {
 	int context_id;
 	register u32 r0 asm("r0") = SCM_ATOMIC(svc, cmd, 1);
@@ -312,7 +312,7 @@
  * This shall only be used with commands that are guaranteed to be
  * uninterruptable, atomic and SMP safe.
  */
-u32 scm_call_atomic2(u32 svc, u32 cmd, u32 arg1, u32 arg2)
+s32 scm_call_atomic2(u32 svc, u32 cmd, u32 arg1, u32 arg2)
 {
 	int context_id;
 	register u32 r0 asm("r0") = SCM_ATOMIC(svc, cmd, 2);