sandbox: Rename sb_cmdline_option to sandbox_cmdline_option

The new name is longer but more clearly related to sandbox.

This is in a separate patch within the same series since some comments on the
SPI series rely on it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Hung-ying Tyan <tyanh@chromium.org>
diff --git a/arch/sandbox/include/asm/sections.h b/arch/sandbox/include/asm/sections.h
index 4c37860..fbc1bd1 100644
--- a/arch/sandbox/include/asm/sections.h
+++ b/arch/sandbox/include/asm/sections.h
@@ -11,9 +11,9 @@
 
 #include <asm-generic/sections.h>
 
-struct sb_cmdline_option;
+struct sandbox_cmdline_option;
 
-extern struct sb_cmdline_option *__u_boot_sandbox_option_start[],
+extern struct sandbox_cmdline_option *__u_boot_sandbox_option_start[],
 	*__u_boot_sandbox_option_end[];
 
 static inline size_t __u_boot_sandbox_option_count(void)