arm: move C runtime setup code in crt0.S

Move all the C runtime setup code from every start.S
in arch/arm into arch/arm/lib/crt0.S. This covers
the code sequence from setting up the initial stack
to calling into board_init_r().

Also, rewrite the C runtime setup and make functions
board_init_*() and relocate_code() behave according to
normal C semantics (no jumping across the C stack any
more, etc).

Some SPL targets had to be touched because they use
start.S explicitly or for some reason; the relevant
maintainers and custodians are cc:ed.

Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
diff --git a/include/configs/socfpga_cyclone5.h b/include/configs/socfpga_cyclone5.h
index 42077bd..5633d2a 100644
--- a/include/configs/socfpga_cyclone5.h
+++ b/include/configs/socfpga_cyclone5.h
@@ -65,7 +65,7 @@
 #define CONFIG_SYS_BOOTMAPSZ		((256*1024*1024) - (4*1024))
 
 #define CONFIG_SPL_RAM_DEVICE
-#define CONFIG_SPL_STACK (&__stack_start)
+#define CONFIG_SPL_STACK CONFIG_SYS_INIT_SP_ADDR
 #define CONFIG_SYS_SPL_MALLOC_START ((unsigned long) (&__malloc_start))
 #define CONFIG_SYS_SPL_MALLOC_SIZE (&__malloc_end - &__malloc_start)