meson: Relax -Wmaybe-uninitialized errors

Suggested-by: @eric

Signed-off-by: Valentine Burley <valentine.burley@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35853>

meson.build

@@ -1131,6 +1131,7 @@ else
     '-Werror=int-conversion',
     '-Wimplicit-fallthrough',
     '-Wmisleading-indentation',
+    '-Wno-error=maybe-uninitialized',
     '-Wno-missing-field-initializers',
     '-Wno-format-truncation',
     '-Wno-nonnull-compare',
@@ -1147,6 +1148,7 @@ else
     '-Werror=return-type',
     '-Werror=empty-body',
     '-Wmisleading-indentation',
+    '-Wno-error=maybe-uninitialized',
     '-Wno-non-virtual-dtor',
     '-Wno-missing-field-initializers',
     '-Wno-format-truncation',