dev: gcdb: Add memory write command on spi post_on for GC9305

For GC9305 panel, need to send the memory write command(0x2C)
before sending pixel data, add memory write command into SPI
display post_on to keep panel continue to receive pixel data.

Change-Id: Ia2d9b3458a5d2e03f117f7f97e34403820bc1c29
1 file changed