x86/64: Enable GPIO sysfs & GPIO LED support

The following changes enables GPIO sysfs as well as the LEDS_GPIO option
within the kernel. This is required to enable LEDs over a GPIO
interface.

Signed-off-by: Chris Blake <chrisrblake93@gmail.com>

target/linux/x86/64/config-default

@@ -109,6 +109,14 @@ CONFIG_GART_IOMMU=y
 CONFIG_GENERIC_BUG_RELATIVE_POINTERS=y
 CONFIG_GENERIC_CPU=y
 CONFIG_GENERIC_PENDING_IRQ=y
+CONFIG_GPIOLIB=y
+# CONFIG_GPIO_104_IDIO_16 is not set
+# CONFIG_GPIO_AMDPT is not set
+# CONFIG_GPIO_F7188X is not set
+# CONFIG_GPIO_INTEL_MID is not set
+# CONFIG_GPIO_IT87 is not set
+# CONFIG_GPIO_LYNXPOINT is not set
+CONFIG_GPIO_SYSFS=y
 CONFIG_HAVE_ACPI_APEI=y
 CONFIG_HAVE_ACPI_APEI_NMI=y
 # CONFIG_HAVE_AOUT is not set
@@ -161,6 +169,7 @@ CONFIG_ITCO_WDT=y
 # CONFIG_KVM_DEBUG_FS is not set
 CONFIG_KVM_GUEST=y
 # CONFIG_LCD_CLASS_DEVICE is not set
+CONFIG_LEDS_GPIO=y
 # CONFIG_LEGACY_VSYSCALL_EMULATE is not set
 # CONFIG_LEGACY_VSYSCALL_NATIVE is not set
 CONFIG_LEGACY_VSYSCALL_NONE=y