ARM: configs: at91: Modernize UBI defconfig part

UBI_GLUEBI is not so common and UBI_FASTMAP is used for several years.
Make them part of a modernization of UBI defconfig options.
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>

arch/arm/configs/at91_dt_defconfig

@@ -54,7 +54,7 @@ CONFIG_MTD_RAW_NAND=y
 CONFIG_MTD_NAND_ATMEL=y
 CONFIG_MTD_SPI_NOR=y
 CONFIG_MTD_UBI=y
-CONFIG_MTD_UBI_GLUEBI=y
+CONFIG_MTD_UBI_FASTMAP=y
 CONFIG_BLK_DEV_LOOP=y
 CONFIG_BLK_DEV_RAM=y
 CONFIG_BLK_DEV_RAM_COUNT=4

arch/arm/configs/sama5_defconfig

@@ -63,7 +63,7 @@ CONFIG_MTD_RAW_NAND=y
 CONFIG_MTD_NAND_ATMEL=y
 CONFIG_MTD_SPI_NOR=y
 CONFIG_MTD_UBI=y
-CONFIG_MTD_UBI_GLUEBI=y
+CONFIG_MTD_UBI_FASTMAP=y
 CONFIG_BLK_DEV_LOOP=y
 CONFIG_BLK_DEV_RAM=y
 CONFIG_BLK_DEV_RAM_COUNT=4