gcc: do not use BR2_GCC_TARGET_TUNE anymore

Since the BR2_GCC_TARGET_TUNE value is always empty now, there is no
longer a point in using it in the gcc package.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gcc/gcc.mk

@@ -174,9 +174,6 @@ endif
 ifneq ($(call qstrip,$(BR2_GCC_TARGET_ARCH)),)
 HOST_GCC_COMMON_CONF_OPTS += --with-arch=$(BR2_GCC_TARGET_ARCH)
 endif
-ifneq ($(call qstrip,$(BR2_GCC_TARGET_TUNE)),)
-HOST_GCC_COMMON_CONF_OPTS += --with-tune=$(BR2_GCC_TARGET_TUNE)
-endif
 ifneq ($(call qstrip,$(BR2_GCC_TARGET_ABI)),)
 HOST_GCC_COMMON_CONF_OPTS += --with-abi=$(BR2_GCC_TARGET_ABI)
 endif