s3/libsmb: clang: Fix '2nd func call argument is uninitalized value'

s3/libsmb: clang: Fix '2nd func call argument is uninitalized value'

Fixes:

source3/libsmb/clireadwrite.c:805:2: warning: 2nd function call argument is an uninitialized value <--[clang]
        memcpy(state->buf, buf, received);
        ^                  ~~~

Signed-off-by: Noel Power <noel.power@suse.com>
Reviewed-by: Gary Lockyer <gary@catalyst.net.nz>