staging: vchiq: Combine vchiq platform code into single file

Combine the vchiq platform initialization code into a single file by
merging vchiq_2835_arm.c into vchiq_arm.c

Reviewed-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Ojaswin Mujoo <ojaswin98@gmail.com>
Link: https://lore.kernel.org/r/647cad50aa3306d1a49bacff76eaa3130fb363f4.1626882325.git.ojaswin98@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>