irq: make SPARSE_IRQ an optionally hidden option

On ARM, we don't want SPARSE_IRQ to be a user visible option. Make
SPARSE_IRQ visible based on MAY_HAVE_SPARSE_IRQ instead of depending
on HAVE_SPARSE_IRQ.

With this, SPARSE_IRQ is not visible on C6X and ARM.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-sh@vger.kernel.org

kernel/irq/Kconfig

@@ -13,7 +13,7 @@ config GENERIC_HARDIRQS
 # Options selectable by the architecture code
 
 # Make sparse irq Kconfig switch below available
-config HAVE_SPARSE_IRQ
+config MAY_HAVE_SPARSE_IRQ
        bool
 
 # Enable the generic irq autoprobe mechanism
@@ -61,8 +61,7 @@ config IRQ_FORCED_THREADING
        bool
 
 config SPARSE_IRQ
-	bool "Support sparse irq numbering"
-	depends on HAVE_SPARSE_IRQ
+	bool "Support sparse irq numbering" if MAY_HAVE_SPARSE_IRQ
 	---help---
 
 	  Sparse irq numbering is useful for distro kernels that want