Adding the board to the boards/README.md

Signed-off-by: genan2003 <genanomer99@gmail.com>

Author: genan2003

boards/README.md

@@ -97,7 +97,7 @@ but the approximate definitions:
 | [Digilent Arty A-7 100T](arty_e21/README.md)                      | RISC-V RV32IMAC  | SiFive E21     | openocd    | tockloader                  | No            |
 | [MSP432 Evaluation kit MSP432P401R](msp_exp432p401r/README.md)    | ARM Cortex-M4    | MSP432P401R    | openocd    | custom                      | No            |
 | [CY8CPROTO-062-4343W](cy8cproto_62_4343_w/README.md)              | ARM Cortex-M0+   | PSoC62         | openocd    | custom                      | No            |
-
+| [LPCXpresso55S69 Development Board](lpc55s69-evk/README.md)       | ARM Cortex-M33   | LPC55S6x       | custom     | custom                      | No            |
 
 ### Other