splash: Fix build warning on 64 bits CPU

Get below warning on ARM64 platform, because the bmp_load_addr
is defined to u32.

common/splash.c: In function ‘splash_video_logo_load’:
common/splash.c:74:9: warning: cast to pointer from integer
of different size [-Wint-to-pointer-cast]
   74 |  memcpy((void *)bmp_load_addr, bmp_logo_bitmap,

Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com> # bpi-m1+, bpi-m64