add 32-bit bionic implementation for denver arch

Add 32-bit bionic implementation for denver. Use denver version of memcpy/
memset. Use Cortex-A15 version of strlen/strcat/strcpy/strcmp.

Change-Id: I4c6b675f20cf41a29cadf70a11d1635d7df5b30a
diff --git a/libc/arch-arm/arm.mk b/libc/arch-arm/arm.mk
index 89a1ce0..cbc5fa7 100644
--- a/libc/arch-arm/arm.mk
+++ b/libc/arch-arm/arm.mk
@@ -70,7 +70,7 @@
 endif
 cpu_variant_mk := $(LOCAL_PATH)/arch-arm/$(TARGET_$(my_2nd_arch_prefix)CPU_VARIANT)/$(TARGET_$(my_2nd_arch_prefix)CPU_VARIANT).mk
 ifeq ($(wildcard $(cpu_variant_mk)),)
-$(error "TARGET_$(my_2nd_arch_prefix)CPU_VARIANT not set or set to an unknown value. Possible values are cortex-a7, cortex-a8, cortex-a9, cortex-a15, krait. Use generic for devices that do not have a CPU similar to any of the supported cpu variants.")
+$(error "TARGET_$(my_2nd_arch_prefix)CPU_VARIANT not set or set to an unknown value. Possible values are cortex-a7, cortex-a8, cortex-a9, cortex-a15, krait, denver. Use generic for devices that do not have a CPU similar to any of the supported cpu variants.")
 endif
 include $(cpu_variant_mk)
 libc_common_additional_dependencies += $(cpu_variant_mk)