gmp: Enable ASM for ARC again

This commit reverts cdf63517de25 "gmp: disable assembly for arc"
as in GMP v6.1.2 there's already a proper fix for ASM constraints, see
https://gmplib.org/repo/gmp/rev/58879634af3ci

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gmp/gmp.mk

@@ -15,7 +15,7 @@ HOST_GMP_DEPENDENCIES = host-m4
 
 # GMP doesn't support assembly for coldfire or mips r6 ISA yet
 # Disable for ARM v7m since it has different asm constraints
-ifeq ($(BR2_m68k_cf)$(BR2_MIPS_CPU_MIPS32R6)$(BR2_MIPS_CPU_MIPS64R6)$(BR2_ARM_CPU_ARMV7M)$(BR2_arc),y)
+ifeq ($(BR2_m68k_cf)$(BR2_MIPS_CPU_MIPS32R6)$(BR2_MIPS_CPU_MIPS64R6)$(BR2_ARM_CPU_ARMV7M),y)
 GMP_CONF_OPTS += --disable-assembly
 endif