hw/arm: move CONFIG_V7M out of default-devices

We currently select CONFIG_V7M for a bunch of our m-profile devices.
The last sticking point is translate.c which cannot be compiled
without expecting v7m support. Express this dependency in Kconfig
rather than in default devices as a stepping stone to a fully
configurable translate.c.

While we are at it we also need to select ARM_COMPATIBLE_SEMIHOSTING
as that is implied for M profile machines.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Acked-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210707131744.26027-4-alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

default-configs/devices/arm-softmmu.mak

 # Default configuration for arm-softmmu
 
-# TODO: ARM_V7M is currently always required - make this more flexible!
-CONFIG_ARM_V7M=y
-
 # CONFIG_PCI_DEVICES=n
 # CONFIG_TEST_DEVICES=n
 

hw/arm/Kconfig

@@ -296,7 +296,10 @@ config ZYNQ
 
 config ARM_V7M
     bool
+    # currently v7M must be included in a TCG build due to translate.c
+    default y if TCG && (ARM || AARCH64)
     select PTIMER
+    select ARM_COMPATIBLE_SEMIHOSTING
 
 config ALLWINNER_A10
     bool