arm: get_sp() should always be compiled

get_sp() was incorrectly excluded if none of
  CONFIG_SETUP_MEMORY_TAGS
  CONFIG_CMDLINE_TAG
  CONFIG_INITRD_TAG
  CONFIG_SERIAL_TAG
  CONFIG_REVISION_TAG
were defined.

Signed-off-by: Po-Yu Chuang <ratbert@faraday-tech.com>

arch/arm/lib/bootm.c

@@ -327,12 +327,12 @@ void setup_revision_tag(struct tag **in_params)
 }
 #endif  /* CONFIG_REVISION_TAG */
 
-
 static void setup_end_tag (bd_t *bd)
 {
 	params->hdr.tag = ATAG_NONE;
 	params->hdr.size = 0;
 }
+#endif /* CONFIG_SETUP_MEMORY_TAGS || CONFIG_CMDLINE_TAG || CONFIG_INITRD_TAG */
 
 static ulong get_sp(void)
 {
@@ -341,5 +341,3 @@ static ulong get_sp(void)
 	asm("mov %0, sp" : "=r"(ret) : );
 	return ret;
 }
-
-#endif /* CONFIG_SETUP_MEMORY_TAGS || CONFIG_CMDLINE_TAG || CONFIG_INITRD_TAG */