boards: mimxrt1050_evk: Added support for LPSPI1 peripheral

RT1050 has multiple LPSPI peripherals. The simplest to access is LPSPI1,
which can be connected by bridging solder jumpers on the board. Enable
this SPI peripheral, and set it as default for SPI tests.

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>