ixp4xx: add missing config symbol for 2.6.30

SVN-Revision: 19046

target/linux/ixp4xx/config-2.6.30

@@ -82,6 +82,7 @@ CONFIG_I2C_GPIO=y
 # CONFIG_I2C_IOP3XX is not set
 CONFIG_I2C=y
 CONFIG_INITRAMFS_SOURCE=""
+# CONFIG_INPUT_IXP4XX_BEEPER is not set
 CONFIG_IP_MROUTE=y
 CONFIG_IP_PIMSM_V1=y
 CONFIG_IP_PIMSM_V2=y