package/glibc: drop support of ARC 7x0 targets

Synopsys ARC 7x0 family is not supported by glibc. Thus, it is
necessary to prevent selecting glibc while configuring for that
processors family.

Fixes:

  http://autobuild.buildroot.net/results/9f0a4d69aed71a840b1c278a9623c9687207ffc6/
  http://autobuild.buildroot.org/results/fa9960365bd54872762d5e959b98882b86c5e956/

Signed-off-by: Yuriy Kolerov <ykolerov@synopsys.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 5aecb99902c35ed48435d7bd7945a0ff58048940)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/glibc/Config.in

@@ -21,7 +21,7 @@ config BR2_PACKAGE_GLIBC_ARCH_SUPPORTS
 	default y if BR2_x86_64
 	default y if BR2_microblaze
 	default y if BR2_nios2
-	default y if BR2_arc && BR2_ARC_ATOMIC_EXT
+	default y if BR2_arc && BR2_ARC_ATOMIC_EXT && !BR2_arc750d && !BR2_arc770d
 	depends on !BR2_POWERPC_CPU_HAS_SPE
 	depends on BR2_RISCV_ISA_RVA || !BR2_riscv
 	depends on BR2_USE_MMU