mm/zswap.c: delete an error message for a failed memory allocation in zswap_dstmem_pr...

mm/zswap.c: delete an error message for a failed memory allocation in zswap_dstmem_prepare()

Omit an extra message for a memory allocation failure in this function.

This issue was detected by using the Coccinelle software.

Link: http://events.linuxfoundation.org/sites/events/files/slides/LCJ16-Refactor_Strings-WSang_0.pdf
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Markus Elfring <[email protected]>
Cc: Dan Streetman <[email protected]>
Cc: Seth Jennings <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>