Revert "configs/bananapi_m1: use NEON+VFPv4 as FPU strategy"

The gcc man page states that specifying Neon as part of the fpu setting
has no effect, unless the -funsafe-math-optimizations is also specified,
because Neon is not compliant with IEEE 754:
```
    If the selected floating-point hardware includes the NEON extension
    (e.g. -mfpu=neon), note that floating-point operations are not
    generated by GCC's auto-vectorization pass unless
    -funsafe-math-optimizations is also specified. This is because NEON
    hardware does not fully implement the IEEE 754 standard for
    floating-point arithmetic (in particular denormal values are treated
    as zero), so the use of NEON instructions may lead to a loss of
    precision.
```

-funsafe-math-optimizations must be explictly specified per package to
really use NEON as FPU, but it's something that is left to the user as
well as setting BR2_ARM_FPU_NEON_VFPV4. This way the default
BR2_ARM_FPU_VFPV4D16 is used as previously. So let's revert the
offending patch.

This reverts commit aaced92e8c.

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 25ecee3f17)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

configs/bananapi_m1_defconfig

@@ -1,6 +1,5 @@
 BR2_arm=y
 BR2_cortex_a7=y
-BR2_ARM_FPU_NEON_VFPV4=y
 BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_18=y
 BR2_TARGET_GENERIC_ISSUE="Welcome to Bananapi M1"
 BR2_ROOTFS_POST_IMAGE_SCRIPT="support/scripts/genimage.sh"