ARM: socfpga_defconfig: Remove QSPI Sector 4K size force

Remove QSPI Sector 4K size force which is causing QSPI boot
problems with the JFFS2 root filesystem.

Fixes the following error:
     "Magic bitmask 0x1985 not found at ..."

Cc: stable@vger.kernel.org
Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>