fs: sysfs_emit: Remove PAGE_SIZE alignment check

For kernel releases older than 4.20, using the SLUB alloctor will cause
this alignment check to fail as that allocator did NOT align kmalloc
allocations on a PAGE_SIZE boundry.

Remove the check for these older kernels as it is a false-positive and
causes problems on many devices.

Signed-off-by: Lucas Wei <lucaswei@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>