intel_edison_fab_c.c: spi_init_pre on arduino should be called on mraa_init()

It's required to make ADC work as well as the SPI bus

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

src/x86/intel_edison_fab_c.c

@@ -427,8 +427,6 @@ mraa_intel_edison_spi_init_pre(int bus)
         return MRAA_SUCCESS;
     }
 
-    mraa_intel_edison_misc_spi();
-
     mraa_gpio_write(tristate, 0);
 
     mraa_gpio_context io10_out = mraa_gpio_init_raw(258);
@@ -1285,6 +1283,9 @@ mraa_intel_edison_fab_c()
         mraa_gpio_dir(tristate, MRAA_GPIO_OUT);
     }
 
+    // this is required to initialise not just SPI but also the ADC channels
+    mraa_intel_edison_misc_spi();
+
     b->adc_raw = 12;
     b->adc_supported = 10;
     b->pwm_default_period = 5000;