Meet the following boot hang.
"
U-Boot SPL 2019.04-00661-gdc80a012e4 (Apr 25 2019 - 10:31:57 +0800)
Trying to boot from MMC1

U-Boot 2019.04-00661-gdc80a012e4 (Apr 25 2019 - 10:31:57 +0800)

CPU:   Freescale i.MX6Q rev1.5 996 MHz (running at 792 MHz)
CPU:   Automotive temperature grade (-40C to 125C)Reset cause: POR
Model: Freescale i.MX6 Quad SABRE Smart Device Board
Board: MX6-SabreSD
I2C:   ready
DRAM:  1 GiB
Video device 'ipu@2400000' cannot allocate frame buffer memory -ensure the device is set up before relocation
Error binding driver 'ipuv3_video': -28
Video device 'ipu@2800000' cannot allocate frame buffer memory -ensure the device is set up before relocation
Error binding driver 'ipuv3_video': -28
Some drivers failed to bind
Error binding driver 'generic_simple_bus': -28
Some drivers failed to bind
initcall sequence 4ffe4500 failed at call 1780dfb7 (err=-28)
"

1. fdtdec_get_alias_seq will use "video" as base, however in alias node,
   we use ipux, so add new alias for U-Boot dts.
2. DM_VIDEO is enabled, however reserve_video is called before
   relocation, so to make DM_VIDEO work before relocation, need to
   set SYS_MALLOC_F_LEN
3. defconfig is updated with savedefconfig

 Note: I do not have a video panel to test, but with this patch, U-Boot
       boots up again, below log.

"
U-Boot SPL 2019.04-00662-g0b62453bff (Apr 25 2019 - 10:36:31 +0800)
Trying to boot from MMC1

U-Boot 2019.04-00662-g0b62453bff (Apr 25 2019 - 10:36:31 +0800)

CPU:   Freescale i.MX6Q rev1.5 996 MHz (running at 792 MHz)
CPU:   Automotive temperature grade (-40C to 125C) at 34C
Reset cause: POR
Model: Freescale i.MX6 Quad SABRE Smart Device Board
Board: MX6-SabreSD
I2C:   ready
DRAM:  1 GiB
PMIC:  PFUZE100 ID=0x10
MMC:   FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 3
Loading Environment from MMC... *** Warning - bad CRC, using default environment

PCI:   pcie phy link never came up
In:    serial
Out:   serial
Err:   serial
Net:   FEC [PRIME]
Hit any key to stop autoboot:  0
"

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Anatolij Gustschin <agust@denx.de>