ARM: dts: lpc32xx: reparent keypad controller to SIC1

After switching to a new interrupt controller scheme by separating SIC1
and SIC2 from MIC interrupt controller just one SoC keypad controller
was not taken into account, fix it now:

  WARNING: CPU: 0 PID: 1 at kernel/irq/irqdomain.c:524 irq_domain_associate+0x50/0x1b0
  error: hwirq 0x36 is too large for interrupt-controller@40008000
  ...
  lpc32xx_keys 40050000.key: failed to get platform irq
  lpc32xx_keys: probe of 40050000.key failed with error -22

Fixes: 9b8ad3fb

 ("ARM: dts: lpc32xx: reparent SIC1 and SIC2 interrupts from MIC")
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>