arm: board: use __weak
common: board: use __weak
i2c: use __weak
misc: use __weak
pci: use __weak
samsung: board: use __weak
usb: use __weak
video: use __weak
armv7: static for local functions
common: cmd_elf: make do_bootelf_exec static

do_bootelf_exec was a weak function without a prototype nor
and strong version. Just make it static.
ehci-hcd.c: make local functions static
fat: make local functions as static
gpio: make local functions static
image-fit: make local function static
net: fec_mxc: make local functions static
sdhci: make local functions static
serial: make local functions static
spi: make local functions static
tegra: make local functions static
disk/part.c: make local function static