imx-digi-base.inc: Set generic tuning for i.MX8/i.MX9

This replicates meta-imx commit addc08b02f9a, which was added to be able to
re-use packages in i.MX8/i.MX9 builds. Without this change, there are
compilation errors when building recent versions of the onnxruntime package
because some .S files are built with specific -march switches that conflict
with our current tunings. For example, when building for the ccimx8x-sbc-pro:

    cc1: error: switch '-mcpu=cortex-a35+crc+crypto' conflicts with '-march=armv8.2-a+fp16' switch [-Werror]
    [...]HalfGemmKernelNeon.S:151: Error: selected processor does not support `fmla v20.8h,v16.8h,v0.h[0]'

Using the generic tuning solves this issue, and according to the log in the
original meta-imx commit, this has minimal to no impact on binaries, so use
said tuning in all relevant platforms.

Signed-off-by: Gabriel Valcazar <gabriel.valcazar@digi.com>

meta-digi-arm/conf/machine/include/imx-digi-base.inc

@@ -33,6 +33,7 @@ XSERVER = "xserver-xorg \
 # Ship kernel modules
 MACHINE_EXTRA_RRECOMMENDS += "kernel-modules"
 
+# DEFAULTTUNE values ported form meta-freescale (imx-base.inc)
 # Tunes for hard/soft float-point selection. Note that we allow building for
 # thumb support giving distros the chance to enable thumb by setting
 # ARM_INSTRUCTION_SET = "thumb"
@@ -47,6 +48,13 @@ DEFAULTTUNE:mx8x-generic-bsp   ?= "cortexa35-crypto"
 DEFAULTTUNE:mx91-generic-bsp   ?= "cortexa55"
 DEFAULTTUNE:mx93-generic-bsp   ?= "cortexa55"
 
+# DEFAULTTUNE values ported form meta-imx (fsl-imx-base.inc)
+# Set a more generic tuning for code reuse across parts
+DEFAULTTUNE:mx8m-nxp-bsp   ?= "armv8a-crc-crypto"
+DEFAULTTUNE:mx8x-nxp-bsp   ?= "armv8a-crc-crypto"
+DEFAULTTUNE:mx91-nxp-bsp   ?= "armv8a-crc-crypto"
+DEFAULTTUNE:mx93-nxp-bsp   ?= "armv8a-crc-crypto"
+
 INHERIT += "machine-overrides-extender"
 
 #######