LoongArch: Delete unnecessary debugfs checking

Debugfs functions are not supposed to be checked for errors. This
is sort of unusual but it is described in the comments for the
debugfs_create_dir() function. Also debugfs_create_dir() can never
return NULL.

Reviewed-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

LoongArch: Fix debugfs_create_dir() error checking

The debugfs_create_dir() returns ERR_PTR in case of an error and the
correct way of checking it is using the IS_ERR_OR_NULL inline function
rather than the simple null comparision. This patch fixes the issue.

Cc: stable@vger.kernel.org
Suggested-By: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Immad Mir <mirimmad17@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

LoongArch: Add unaligned access support

Loongson-2 series (Loongson-2K500, Loongson-2K1000) don't support
unaligned access in hardware, while Loongson-3 series (Loongson-3A5000,
Loongson-3C5000) are configurable whether support unaligned access in
hardware. This patch add unaligned access emulation for those LoongArch
processors without hardware support.

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>