riscv: dts: microchip: add new peripherals to icicle kit device tree

Add new peripherals to the MPFS, and enable them in the Icicle kit
device tree:

2x SPI, QSPI, 3x GPIO, 2x I2C, Real Time Counter, PCIE controller,
USB host & system controller.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>