configs/imxrt1050-evk: fix build failure due to wrong toolchain
i.MXRT1050 is based on a ARMv7M core and we can't build using ARMV7
toolchain, so let's switch toolchain to
BR2_TOOLCHAIN_EXTERNAL_BOOTLIN_ARMV7M_UCLIBC_STABLE
Fixes:
https://gitlab.com/buildroot.org/buildroot/-/jobs/11393506762
https://gitlab.com/buildroot.org/buildroot/-/commit/fdc002ee38e58ef4abfbd1615217a5977f9a0077
Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
[Julien: add link to commit id introducing the issue]
Signed-off-by: Julien Olivain <ju.o@free.fr>
Giulio Benetti