bcm27xx: bcm2711: update defconfig

bcm27xx: bcm2711: update defconfig

Ran `make kernel_menuconfig CONFIG_TARGET=bcm2711` having used the snapshot
config for bcm2711[1].  Manually added back two symbols that the make target
removed, namely:
* # CONFIG_SND_SOC_AD193X_I2C is not set
* # CONFIG_SND_SOC_AD193X_SPI is not set

Without adding these back, the build fails due to unsatisfied deps[2].

Build system: x86_64
Build-tested: bcm2711/multidevices

1. https://downloads.openwrt.org/snapshots/targets/bcm27xx/bcm2711/config.buildinfo
2. https://github.com/openwrt/openwrt/commit/a478202d74b66c3da17d57442649eb4f131fc7b2#commitcomment-67096592

Signed-off-by: John Audia <graysky@archlinux.us>