mtd: rawnand: intel: remove broken code

Drop the check for mtd->name as it's executed while the mtd variable is
always NULL. If some MTD name is needed then it should be validated by
the MTD core.

While here, also drop the NULL assignment to the mtd variable as it's
overwritten later on anyways and the NULL value is never read.

Fixes: 0b1039f0 ("mtd: rawnand: Add NAND controller support on Intel LGM SoC")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>