drivers: mipi_dbi: mipi_dbi_nxp_lcdic: fix reset pulse calculation

Reset pulse count can be up to 512 before we would be unable to support
it using the peripheral. Use a uint32_t for the count, so that even long
reset pulses will still be calculated correctly. Add code to warn about
reset pulse requests that are too long.

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