spi: spi-imx: Fix compilation error

Fix compilation error due to a typo introduced by commit 24778be2
("spi: convert drivers to use bits_per_word_mask"). Without this patch
we get the following build errors:

drivers/spi/spi-imx.c: In function ‘spi_imx_setupxfer’:
drivers/spi/spi-imx.c:703:2: warning: no return statement in function returning non-void [-Wreturn-type]
drivers/spi/spi-imx.c: At top level:
drivers/spi/spi-imx.c:705:9: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘->’ token
drivers/spi/spi-imx.c:707:2: error: expected identifier or ‘(’ before ‘return’
drivers/spi/spi-imx.c:708:1: error: expected identifier or ‘(’ before ‘}’ token

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>