Revert "spi: Add check for 8-bit transfer with 8 IO mode support"

This reverts commit 82b29ee8 which is
commit 71050521 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I6727c91fc52be0c25b57d9b7f0ba14118b109b8d
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>