arch: cxd56xx: Improve i2c initialize function

During I2C communication between non-Spresense devices is performed,
the I2C bus may freeze after initialization of the Spresense I2C.
As a workaround, switch the pin mode to I2C at the end of the i2c
initialization function.

arch/arm/src/cxd56xx/cxd56_i2c.c

@@ -1140,10 +1140,6 @@ struct i2c_master_s *cxd56_i2cbus_initialize(int port)
 
   cxd56_i2c_setfrequency(priv, I2C_DEFAULT_FREQUENCY);
 
-  /* Configure pin */
-
-  cxd56_i2c_pincontrol(port, true);
-
   /* Attach Interrupt Handler */
 
   irq_attach(priv->irqid, cxd56_i2c_interrupt, priv);
@@ -1164,6 +1160,10 @@ struct i2c_master_s *cxd56_i2cbus_initialize(int port)
 
   cxd56_i2c_clock_gate_enable(port);
 
+  /* Configure pin */
+
+  cxd56_i2c_pincontrol(port, true);
+
   nxmutex_unlock(&priv->lock);
   return &priv->dev;
 }