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>

cmd/i2c.c

@@ -1969,8 +1969,7 @@ static int do_i2c(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 }
 
 /***************************************************/
-#ifdef CONFIG_SYS_LONGHELP
-static char i2c_help_text[] =
+U_BOOT_LONGHELP(i2c,
 #if CONFIG_IS_ENABLED(SYS_I2C_LEGACY) || CONFIG_IS_ENABLED(DM_I2C)
 	"bus [muxtype:muxaddr:muxchannel] - show I2C bus info\n"
 	"i2c " /* That's the prefix for the crc32 command below. */
@@ -1999,8 +1998,7 @@ static char i2c_help_text[] =
 #if defined(CONFIG_CMD_SDRAM)
 	"i2c sdram chip - print SDRAM configuration information\n"
 #endif
-	"i2c speed [speed] - show or set I2C bus speed";
-#endif
+	"i2c speed [speed] - show or set I2C bus speed");
 
 U_BOOT_CMD(
 	i2c, 7, 1, do_i2c,