net/mlx5: Reduce kconfig complexity while building crypto support

Both IPsec and kTLS need two functions declared in the lib/crypto.c
file. These functions are advertised through general mlx5.h file and
don't have any protection from attempts to call them without proper
config option.

Instead of creating stubs just for two functions, simply build that *.c
file as part of regular mlx5_eth build and rely on compiler to throw
them away if no callers exist in produced code.

Link: https://lore.kernel.org/r/37f02171da06886c1b403d44dd18b2a56b19219d.1649232994.git.leonro@nvidia.com
Reviewed-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/Kconfig

@@ -16,9 +16,6 @@ config MLX5_CORE
 	  Core driver for low level functionality of the ConnectX-4 and
 	  Connect-IB cards by Mellanox Technologies.
 
-config MLX5_ACCEL
-	bool
-
 config MLX5_FPGA
 	bool "Mellanox Technologies Innova support"
 	depends on MLX5_CORE
@@ -147,7 +144,6 @@ config MLX5_EN_IPSEC
 	depends on MLX5_CORE_EN
 	depends on XFRM_OFFLOAD
 	depends on INET_ESP_OFFLOAD || INET6_ESP_OFFLOAD
-	select MLX5_ACCEL
 	help
 	  Build support for IPsec cryptography-offload acceleration in the NIC.
 
@@ -156,7 +152,6 @@ config MLX5_EN_TLS
 	depends on TLS_DEVICE
 	depends on TLS=y || MLX5_CORE=m
 	depends on MLX5_CORE_EN
-	select MLX5_ACCEL
 	help
 	Build support for TLS cryptography-offload acceleration in the NIC.
 

drivers/net/ethernet/mellanox/mlx5/core/Makefile

@@ -28,7 +28,7 @@ mlx5_core-$(CONFIG_MLX5_CORE_EN) += en/rqt.o en/tir.o en/rss.o en/rx_res.o \
 		en_selftest.o en/port.o en/monitor_stats.o en/health.o \
 		en/reporter_tx.o en/reporter_rx.o en/params.o en/xsk/pool.o \
 		en/xsk/setup.o en/xsk/rx.o en/xsk/tx.o en/devlink.o en/ptp.o \
-		en/qos.o en/trap.o en/fs_tt_redirect.o en/selq.o
+		en/qos.o en/trap.o en/fs_tt_redirect.o en/selq.o lib/crypto.o
 
 #
 # Netdev extra
@@ -88,8 +88,6 @@ mlx5_core-$(CONFIG_MLX5_CORE_IPOIB) += ipoib/ipoib.o ipoib/ethtool.o ipoib/ipoib
 #
 # Accelerations & FPGA
 #
-mlx5_core-$(CONFIG_MLX5_ACCEL) += lib/crypto.o
-
 mlx5_core-$(CONFIG_MLX5_FPGA) += fpga/cmd.o fpga/core.o fpga/conn.o fpga/sdk.o
 
 mlx5_core-$(CONFIG_MLX5_EN_IPSEC) += en_accel/ipsec.o en_accel/ipsec_rxtx.o \