cmd: gpt: fix and tidy up help message

Apply the following changes:
 - Guard the 'gpt read' command by 'ifdef CONFIG_CMD_GPT_RENAME',
   since 'gpt read' is not available on CMD_GPT_RENAME=n
 - Prefix the {read,swap,rename} commands with one space for consistency
 - Prefix the 'guid' commands with 'gpt' for consistency

Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
1 file changed