mfd: vexpress: Define the device as MFD cells

This patch - finally, after over 6 months! :-( - addresses
Samuel's request to split the vexpress-sysreg driver into
smaller portions and define the device in a form of MFD
cells:

* LEDs code has been completely removed and replaced with
  "gpio-leds" nodes in the tree (referencing dedicated
  GPIO subnodes in sysreg - bindings documentation updated);
  this also better fits the reality as some variants of the
  motherboard don't have all the LEDs populated

* syscfg bridge code has been extracted into a separate
  driver (placed in drivers/misc for no better place)

* all the ID & MISC registers are defined as sysconf
  making them available for other drivers should they need
  to use them (and also to the user via /sys/kernel/debug/regmap
  which can be helpful in platform debugging)

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Acked-by: Lee Jones <lee.jones@linaro.org>

arch/arm/boot/dts/vexpress-v2m.dtsi

@@ -73,8 +73,24 @@
 			v2m_sysreg: sysreg@00000 {
 				compatible = "arm,vexpress-sysreg";
 				reg = <0x00000 0x1000>;
-				gpio-controller;
-				#gpio-cells = <2>;
+
+				v2m_led_gpios: sys_led@08 {
+					compatible = "arm,vexpress-sysreg,sys_led";
+					gpio-controller;
+					#gpio-cells = <2>;
+				};
+
+				v2m_mmc_gpios: sys_mci@48 {
+					compatible = "arm,vexpress-sysreg,sys_mci";
+					gpio-controller;
+					#gpio-cells = <2>;
+				};
+
+				v2m_flash_gpios: sys_flash@4c {
+					compatible = "arm,vexpress-sysreg,sys_flash";
+					gpio-controller;
+					#gpio-cells = <2>;
+				};
 			};
 
 			v2m_sysctl: sysctl@01000 {
@@ -112,8 +128,8 @@
 				compatible = "arm,pl180", "arm,primecell";
 				reg = <0x05000 0x1000>;
 				interrupts = <9 10>;
-				cd-gpios = <&v2m_sysreg 0 0>;
-				wp-gpios = <&v2m_sysreg 1 0>;
+				cd-gpios = <&v2m_mmc_gpios 0 0>;
+				wp-gpios = <&v2m_mmc_gpios 1 0>;
 				max-frequency = <12000000>;
 				vmmc-supply = <&v2m_fixed_3v3>;
 				clocks = <&v2m_clk24mhz>, <&smbclk>;
@@ -264,6 +280,58 @@
 			clock-output-names = "v2m:refclk32khz";
 		};
 
+		leds {
+			compatible = "gpio-leds";
+
+			user@1 {
+				label = "v2m:green:user1";
+				gpios = <&v2m_led_gpios 0 0>;
+				linux,default-trigger = "heartbeat";
+			};
+
+			user@2 {
+				label = "v2m:green:user2";
+				gpios = <&v2m_led_gpios 1 0>;
+				linux,default-trigger = "mmc0";
+			};
+
+			user@3 {
+				label = "v2m:green:user3";
+				gpios = <&v2m_led_gpios 2 0>;
+				linux,default-trigger = "cpu0";
+			};
+
+			user@4 {
+				label = "v2m:green:user4";
+				gpios = <&v2m_led_gpios 3 0>;
+				linux,default-trigger = "cpu1";
+			};
+
+			user@5 {
+				label = "v2m:green:user5";
+				gpios = <&v2m_led_gpios 4 0>;
+				linux,default-trigger = "cpu2";
+			};
+
+			user@6 {
+				label = "v2m:green:user6";
+				gpios = <&v2m_led_gpios 5 0>;
+				linux,default-trigger = "cpu3";
+			};
+
+			user@7 {
+				label = "v2m:green:user7";
+				gpios = <&v2m_led_gpios 6 0>;
+				linux,default-trigger = "cpu4";
+			};
+
+			user@8 {
+				label = "v2m:green:user8";
+				gpios = <&v2m_led_gpios 7 0>;
+				linux,default-trigger = "cpu5";
+			};
+		};
+
 		mcc {
 			compatible = "arm,vexpress,config-bus";
 			arm,vexpress,config-bridge = <&v2m_sysreg>;