ARM: tegra: call cpu_do_idle from C code

When building a kernel for multiple CPU architecture levels,
cpu_do_idle() is a macro for an indirect function call, which
cannot be called from assembly code as Tegra does.

Adding a trivial C wrapper for this function lets us build
a tegra kernel with ARMv6 support enabled.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Joseph Lo <josephl@nvidia.com>
Cc: Stephen Warren <swarren@nvidia.com>

arch/arm/mach-tegra/pm.c

@@ -162,6 +162,11 @@ bool tegra_set_cpu_in_lp2(int phy_cpu_id)
 	return last_cpu;
 }
 
+int tegra_cpu_do_idle(void)
+{
+	return cpu_do_idle();
+}
+
 static int tegra_sleep_cpu(unsigned long v2p)
 {
 	/* Switch to the identity mapping. */

arch/arm/mach-tegra/sleep-tegra20.S

@@ -197,7 +197,7 @@ ENTRY(tegra20_sleep_cpu_secondary_finish)
 	mov	r3, #CPU_RESETTABLE
 	str	r3, [r0]
 
-	bl	cpu_do_idle
+	bl	tegra_cpu_do_idle
 
 	/*
 	 * cpu may be reset while in wfi, which will return through