memory: emif: Remove bogus debugfs error handling

[ Upstream commit fd22781648080cc400772b3c68aa6b059d2d5420 ]

Callers are generally not supposed to check the return values from
debugfs functions.  Debugfs functions never return NULL so this error
handling will never trigger.  (Historically debugfs functions used to
return a mix of NULL and error pointers but it was eventually deemed too
complicated for something which wasn't intended to be used in normal
situations).

Delete all the error handling.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Link: https://lore.kernel.org/r/20200826113759.GF393664@mwanda


Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>