regmap: clean up regmap allocation

Putting zero length array at the end of struct is a common technique
to embed arbitrary length of members.  There is no good reason to let
regmap_alloc_count() branch by "if (count <= 1)".

As far as I understood the code, regmap->base is an alias of
regmap->ranges[0].start, but it is not helpful but make the code
just ugly.

Rename regmap_alloc_count() to regmap_alloc() because the _count
suffix seems pointless.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
[trini: fixup cpu_info-rcar.c]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/mach-rmobile/cpu_info-rcar.c b/arch/arm/mach-rmobile/cpu_info-rcar.c
index fbff55e..ccb7a32 100644
--- a/arch/arm/mach-rmobile/cpu_info-rcar.c
+++ b/arch/arm/mach-rmobile/cpu_info-rcar.c
@@ -74,7 +74,7 @@
 		hang();
 	}
 
-	return readl(map->base);
+	return readl(map->ranges[0].start);
 }
 
 static const struct udevice_id renesas_prr_ids[] = {