drivers/spi/atmel_spi.c: Fix GCC 4.6 warning

Fix:
atmel_spi.c: In function 'spi_xfer':
atmel_spi.c:139:7: warning: variable 'ret' set but not used
[-Wunused-but-set-variable]

Signed-off-by: Anatolij Gustschin <agust@denx.de>
1 file changed