tplink-safeloader: add TP-Link Deco M4R v1 and v2 support

tplink-safeloader: add TP-Link Deco M4R v1 and v2 support

Support creating images for TP-Link Deco M4R v1 and v2.

Original partition layout from OEM image:
 partition fs-uboot base 0x00000 size 0x80000
 partition os-image base 0x80000 size 0x200000
 partition file-system base 0x280000 size 0xc00000
 partition product-info base 0xe80000 size 0x05000
 partition default-mac base 0xe85000 size 0x01000
 partition device-id base 0xe86000 size 0x01000
 partition support-list base 0xe87000 size 0x10000
 partition user-config base 0xea7000 size 0x10000
 partition device-config base 0xeb7000 size 0x10000
 partition group-info base 0xec7000 size 0x10000
 partition partition-table base 0xed7000 size 0x02000
 partition soft-version base 0xed9000 size 0x10000
 partition profile base 0xee9000 size 0x10000
 partition default-config base 0xef9000 size 0x10000
 partition url-sig base 0xfe0000 size 0x10000
 partition radio base 0xff0000 size 0x10000

The 'os-image' and 'file-system' partitions were merged into 'firmware'
to make use of the automatic mtd split.

The first 2 versions of the device use the same firmware image,
v3 and v4 are different.

Signed-off-by: Foica David <superh552@gmail.com>