microblaze: Setup dependencies for ASM optimized lib functions

The patch:
"microblaze: Setup proper dependency for optimized lib functions"
(sha1: 7b6ce52b

)
didn't setup all dependencies properly.
Optimized lib functions in C are also present for little endian
and optimized library functions in assembler are implemented only for
big endian version.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>