staging: r8188eu: Use zeroing allocator in wpa_set_encryption()

Use zeroing allocator rather than allocator followed by memset with 0.

This issue was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20211012024624.GA1062447@embeddedor


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>