[Keyboard] Handle timeout on UART for Redox Wireless (#17203)

* Handle timeout on UART for Redox Wireless receiver-to-keyboard communication.

- This fixes the issue of a keyboard deadlocking on the first matrix
  scan with Redox Wireless keyboards

* Remove an explicit cast.

Co-authored-by: Tomasz Janeczko <tomasz.j@hey.com>

keyboards/redox_w/matrix.c

@@ -18,6 +18,8 @@
 #include "matrix.h"
 #include "uart.h"
 
+#define UART_MATRIX_RESPONSE_TIMEOUT 10000
+
 void matrix_init_custom(void) {
     uart_init(1000000);
 }
@@ -39,11 +41,16 @@ bool matrix_scan_custom(matrix_row_t current_matrix[]) {
         //harm to leave it in here
         while (!uart_available()) {
             timeout++;
-            if (timeout > 10000) {
+            if (timeout > UART_MATRIX_RESPONSE_TIMEOUT) {
                 break;
             }
         }
+
+        if (timeout < UART_MATRIX_RESPONSE_TIMEOUT) {
             uart_data[i] = uart_read();
+        } else {
+            uart_data[i] = 0x00;
+        }
     }
 
     //check for the end packet, the key state bytes use the LSBs, so 0xE0