ARMV7: Fix build for non-OMAP3 boards

Commit c3d3a541 uses CONFIG_ARMV7 to determine whether to call the
v7_flush_cache_all function.  This breaks the build for all non-OMAP3
boards (like Panda and OMAP4430SDP) since there is only a v7_flush_cache_all
implementation for OMAP3.

This patch uses CONFIG_OMAP3XXX instead of CONFIG_ARMV7 so that only boards
with a v7_flush_cache_all will make the call.

Tested on Beagle, Overo, Panda, and OMAP4430SDP

Signed-off-by: Steve Sakoman <steve.sakoman@linaro.org>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>

arch/arm/lib/cache.c

@@ -38,7 +38,7 @@ void  flush_cache (unsigned long dummy1, unsigned long dummy2)
 	/* disable write buffer as well (page 2-22) */
 	asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (0));
 #endif
-#ifdef CONFIG_ARMV7
+#ifdef CONFIG_OMAP34XX
 	void v7_flush_cache_all(void);
 
 	v7_flush_cache_all();