soc: fsl: guts: Revert commit 3c0d64e8

This reverts commit 3c0d64e8
("soc: fsl: guts: reuse machine name from device tree").

A following patch will fix the missing memory allocation failure check
instead.

Suggested-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Li Yang <leoyang.li@nxp.com>