ARM: dts: lpc32xx: Update spi clock properties

ARM: dts: lpc32xx: Update spi clock properties

PL022 binding require two clocks to be defined but NXP LPC32xx platform
doesn't comply with the bindings and define only one clock i.e apb_pclk.

Update SPI clocks and clocks-names property by adding appropriate clock
reference to make it compliant with the bindings.

Noteworthy, strictly speaking the change tackles DT ABI by changing
the order in the list of clock-names property values, however this level
of impact is considered as acceptable.

Cc: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Kuldeep Singh <singh.kuldeep87k@gmail.com>
[vzapolskiy: rebased and minor update to the commit message]
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>