rds: debug messages are enabled by default

rds use Kconfig option called "RDS_DEBUG" to enable rds debug messages.
This option cause the rds Makefile to add -DDEBUG to the rds gcc command
line.

When CONFIG_DYNAMIC_DEBUG is enabled, the "DEBUG" macro is used by
include/linux/dynamic_debug.h to decide if dynamic debug prints should
be sent by default to the kernel log.

rds should not enable this macro for production builds. rds dynamic
debug work as expected follow this fix.

Signed-off-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Reviewed-by: Wengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>