cmd: Convert existing long help messages to the new macro

- Generally we just drop the #ifdef CONFIG_SYS_LONGHELP and endif lines
and use U_BOOT_LONGHELP to declare the same variable name as before
- In a few places, either rename the variable to follow convention or
introduce the variable as it was being done inline before.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

cat: Update command to use fs_load_alloc()

Use this new function since it implements the required functionality and
reduces duplicated code.

Signed-off-by: Simon Glass <sjg@chromium.org>

cmd: cat: add new command

Add cat command to print file content to standard out

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Roger Knecht <rknecht@pm.me>

cat: Update command to use fs_load_alloc()

Use this new function since it implements the required functionality and
reduces duplicated code.

Signed-off-by: Simon Glass <sjg@chromium.org>

cmd: cat: add new command

Add cat command to print file content to standard out

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Roger Knecht <rknecht@pm.me>

cmd: cat: add new command

Add cat command to print file content to standard out

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Roger Knecht <rknecht@pm.me>