net/memac_phy: reuse driver for little endian SoCs

The memac for PHY management on little endian SoCs is similar on big
endian SoCs, so we modify the driver by using I/O accessor function to
handle the endianness, so the driver can be reused on little endian
SoCs, we introduce CONFIG_SYS_MEMAC_LITTLE_ENDIAN for little endian
SoCs, if the CONFIG_SYS_MEMAC_LITTLE_ENDIAN is defined, the I/O access
is little endian, if not, the I/O access is big endian. Move fsl_memac.h
out of powerpc include.

Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Signed-off-by: York Sun <yorksun@freescale.com>
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 00a930c..150470c 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -70,4 +70,5 @@
 obj-$(CONFIG_ZYNQ_GEM) += zynq_gem.o
 obj-$(CONFIG_FSL_MC_ENET) += fsl-mc/
 obj-$(CONFIG_FSL_MC_ENET) += ldpaa_eth/
+obj-$(CONFIG_FSL_MEMAC) += fm/memac_phy.o
 obj-$(CONFIG_VSC9953) += vsc9953.o