chore(card10-board): Fix a sign-compare warning

Fix the following warning:

    lib/sdk/Libraries/Boards/card10/Source/board.c: In function 'Board_Init':
    lib/sdk/Libraries/Boards/card10/Source/board.c:102:19: warning:
             comparison of integer expressions of different signedness:
             'int' and 'unsigned int' [-Wsign-compare]
      102 |     for (i = 0; i < num_pins; i++) {
          |                   ^

Signed-off-by: Rahix <rahix@rahix.de>