microblaze: spl: configure SYS_MALLOC_F_LEN independently for SPL and full U-Boot

Some platforms have very limited SRAM to run SPL code, so there may
not be the same amount space for a malloc pool before relocation in
the SPL stage as the normal U-Boot stage.

Make SPL and (the full) U-Boot stage use independent SYS_MALLOC_F_LEN,
so the size of pre-relocation malloc pool can be configured memory
space independently.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
[fixed up commit-message:]
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

arch/microblaze/cpu/start.S

@@ -31,8 +31,8 @@ _start:
 	mts	rshr, r1
 	addi	r1, r1, -4	/* Decrement SP to top of memory */
 #else
-#if defined(CONFIG_SYS_MALLOC_F_LEN)
-	addi	r1, r0, CONFIG_SYS_INIT_SP_OFFSET - CONFIG_SYS_MALLOC_F_LEN
+#if CONFIG_VAL(SYS_MALLOC_F_LEN)
+	addi	r1, r0, CONFIG_SYS_INIT_SP_OFFSET - CONFIG_VAL(SYS_MALLOC_F_LEN)
 #else
 	addi	r1, r0, CONFIG_SYS_INIT_SP_OFFSET
 #endif
@@ -162,14 +162,14 @@ clear_bss:
 #ifndef CONFIG_SPL_BUILD
 	or	r5, r0, r0	/* flags - empty */
 	addi    r31, r0, _gd
-#if defined(CONFIG_SYS_MALLOC_F_LEN)
+#if CONFIG_VAL(SYS_MALLOC_F_LEN)
 	addi	r6, r0, CONFIG_SYS_INIT_SP_OFFSET
 	swi	r6, r31, GD_MALLOC_BASE
 #endif
 	brai	board_init_f
 #else
 	addi	r31, r0, _gd
-#if defined(CONFIG_SYS_MALLOC_F_LEN)
+#if CONFIG_VAL(SYS_MALLOC_F_LEN)
 	addi	r6, r0, CONFIG_SPL_STACK_ADDR
 	swi	r6, r31, GD_MALLOC_BASE
 #endif