[PATCH] doc: sandbox: Correct the memory size config option

[Bin Meng]

It should be CONFIG_SANDBOX_RAM_SIZE_MB.

Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
---

 doc/arch/sandbox.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/arch/sandbox.rst b/doc/arch/sandbox.rst
index bc670b98b7..246ab5b380 100644
--- a/doc/arch/sandbox.rst
+++ b/doc/arch/sandbox.rst
@@ -143,7 +143,7 @@ UBOOT_SB_TIME_OFFSET
 Memory Emulation
 ----------------
 
-Memory emulation is supported, with the size set by CONFIG_SYS_SDRAM_SIZE.
+Memory emulation is supported, with the size set by CONFIG_SANDBOX_RAM_SIZE_MB.
 The -m option can be used to read memory from a file on start-up and write
 it when shutting down. This allows preserving of memory contents across
 test runs. You can tell U-Boot to remove the memory file after it is read
-- 
2.25.1