MIPS: brcmstb: remove useless includes

Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>
MIPS: brcmstb: remove useless functions

Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>
MIPS: brcmstb: add missing header

Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>
MIPS: brcmstb: remove mtd.c

Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>
MIPS: brcmstb: update defconfig of all boards

Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>
MIPS: brcmstb: remove useless codes

Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>