cmd: Move meminfo command into its own file

In preparation for expanding this command, move it into a separate file.
Rename the function to remove the extra underscore. Update the number of
arguments to 1, since 3 is incorrect.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

cmd/Kconfig

@@ -885,6 +885,7 @@ config MD5SUM_VERIFY
 
 config CMD_MEMINFO
 	bool "meminfo"
+	default y if SANDBOX
 	help
 	  Display memory information.
 

cmd/Makefile

@@ -110,6 +110,7 @@ obj-$(CONFIG_CMD_LOG) += log.o
 obj-$(CONFIG_CMD_LSBLK) += lsblk.o
 obj-$(CONFIG_CMD_MD5SUM) += md5sum.o
 obj-$(CONFIG_CMD_MEMORY) += mem.o
+obj-$(CONFIG_CMD_MEMINFO) += meminfo.o
 obj-$(CONFIG_CMD_IO) += io.o
 obj-$(CONFIG_CMD_MII) += mii.o
 obj-$(CONFIG_CMD_MISC) += misc.o

cmd/mem.c

@@ -1379,17 +1379,6 @@ U_BOOT_CMD(
 
 #endif
 
-#ifdef CONFIG_CMD_MEMINFO
-static int do_mem_info(struct cmd_tbl *cmdtp, int flag, int argc,
-		       char *const argv[])
-{
-	puts("DRAM:  ");
-	print_size(gd->ram_size, "\n");
-
-	return 0;
-}
-#endif
-
 U_BOOT_CMD(
 	base,	2,	1,	do_mem_base,
 	"print or set address offset",
@@ -1433,14 +1422,6 @@ U_BOOT_CMD(
 );
 #endif /* CONFIG_CMD_MX_CYCLIC */
 
-#ifdef CONFIG_CMD_MEMINFO
-U_BOOT_CMD(
-	meminfo,	3,	1,	do_mem_info,
-	"display memory information",
-	""
-);
-#endif
-
 #ifdef CONFIG_CMD_RANDOM
 U_BOOT_CMD(
 	random,	4,	0,	do_random,

cmd/meminfo.c

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2024 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <command.h>
+#include <display_options.h>
+#include <asm/global_data.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static int do_meminfo(struct cmd_tbl *cmdtp, int flag, int argc,
+		       char *const argv[])
+{
+	puts("DRAM:  ");
+	print_size(gd->ram_size, "\n");
+
+	return 0;
+}
+
+U_BOOT_CMD(
+	meminfo,	1,	1,	do_meminfo,
+	"display memory information",
+	""
+);