mmc: core: Delete error messages for failed memory allocations

Omit an extra message for memory allocation failures.

This issue was detected by using the Coccinelle software.

Link: http://events.linuxfoundation.org/sites/events/files/slides/LCJ16-Refactor_Strings-WSang_0.pdf


Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>