microblaze: fix endian handling

microblaze: fix endian handling

commit 71e7673dadfdae0605d4c1f66ecb4b045c79fe0f upstream.

Building an allmodconfig kernel fails horribly because of
endian mismatch. It turns out that the -mlittle-endian
switch was not honored at all as we were using the wrong
Kconfig symbol and failing to apply CPUFLAGS to the CFLAGS.
Finally, the linker flags did not get set right.

This addresses all three of those issues, which now lets
me build both big-endian and little-endian kernels for
testing.

Fixes: 428dbf156cc5 ("arch: change default endian for microblaze")
Fixes: 206d3642d8ee ("arch/microblaze: add choice for endianness and update Makefile")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>