fastboot: mmc: extend flash/erase for both emmc hwpart 1 and 2

Update the code and the configs for eMMC boot and userdata
partitions acces
- FASTBOOT_MMC_BOOT_SUPPORT: boot partition 1 and 2 (erase/write)
- FASTBOOT_MMC_BOOT1_NAME: boot partition 1, default name="mmc0boot0"
- FASTBOOT_MMC_BOOT2_NAME: boot partition 2, default name="mmc0boot1"

This patch also removes the unnecessary dependency with
ARCH_MEDIATEK and EFI_PARTITION.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
diff --git a/configs/pumpkin_defconfig b/configs/pumpkin_defconfig
index a9655f5..5270ec2 100644
--- a/configs/pumpkin_defconfig
+++ b/configs/pumpkin_defconfig
@@ -52,7 +52,7 @@
 CONFIG_FASTBOOT_BUF_SIZE=0x4000000
 CONFIG_FASTBOOT_FLASH=y
 CONFIG_FASTBOOT_FLASH_MMC_DEV=0
-CONFIG_FASTBOOT_MMC_BOOT1_SUPPORT=y
+CONFIG_FASTBOOT_MMC_BOOT_SUPPORT=y
 CONFIG_FASTBOOT_MMC_USER_SUPPORT=y
 # CONFIG_INPUT is not set
 CONFIG_DM_MMC=y