ARM: orion5x: Fix legacy get_irqnr_and_base

Commit 5be9fc2 ("ARM: orion5x: fix legacy orion5x IRQ numbers") shifted
IRQ numbers by one but didn't update the get_irqnr_and_base macro
accordingly.  This macro is involved when CONFIG_MULTI_IRQ_HANDLER
is not defined.

[jac: 5d6bed2 went in to v4.2, but was backported to v3.18]

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Fixes: 5be9fc2 ("ARM: orion5x: fix legacy orion5x IRQ numbers")
Cc: <stable@vger.kernel.org> # v3.18+
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

Author: Nicolas Pitre

arch/arm/mach-orion5x/include/mach/entry-macro.S

@@ -21,5 +21,5 @@
 	@ find cause bits that are unmasked
 	ands	\irqstat, \irqstat, \tmp	@ clear Z flag if any
 	clzne	\irqnr,	\irqstat		@ calc irqnr
-	rsbne	\irqnr, \irqnr, #31
+	rsbne	\irqnr, \irqnr, #32
 	.endm