Leave clock alone if RTC driver is active

Variant of previous fix but that doesn't corrupt R0.
Retagged as SDCMOS-0_12.

s/sdcmos

@@ -299,10 +299,6 @@ TryInit ROUT
         TEQ     r14, r5
         BNE     %B50
 
-        ; If there's no RTC, try restoring the time from the HAL timestamp
-        SWI     XRTC_Features
-        BVC     %F60        ; V clear -> RTC driver is active
-
         ; Read size of pseudo CMOS in HAL
         MOV     r2, sp
         MOV     r3, #4
@@ -310,6 +306,10 @@ TryInit ROUT
         BVS     %F60
         LDR     r6, [sp]
 
+        ; If there's no RTC, try restoring the time from the HAL timestamp
+        SWI     XRTC_Features
+        BVC     %F60        ; V clear -> RTC driver is active
+
         ; Read the last timestamp
         MOV     r0, #OSGBPB_ReadFromGiven
         MOV     r2, sp