ARM: dts: dra7-evm: fix qspi device tree partition size

commit 69d2626f97b7f017ee4416b7dc071e9499c2c944 upstream.

64KiB is allocated for qspi dtb partition which is not
sufficient, so updating the partition table size to 512KiB
for device tree partition.

This also aligns the QSPI partition definitions between
kernel and U-Boot.

Fixes: dc2dd5b8 ("ARM: dts: dra7: Add qspi device")

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>