zephyr: emul: move ln9310 reg bytes checking
zephyr: emul: move ln9310 reg bytes checking

The ln9310 emulator is consistent in its use of the bytes parameter in
reg read write operations.

Move bytes parameter verification to top of read/write register
operations.

BRANCH=none
BUG=None
TEST=zmake configure --test test-drivers

Signed-off-by: Aaron Massey <79529a820df71f45023239a3663736629646cc34@google.com>
Change-Id: Ia1732aef8a9e076193bea2ee3ef12bbfb87fcc05
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3285636
Reviewed-by: Wai-Hong Tam <04b587fdf5845741a0c5a8b9cd59ca72d73ef8fc@google.com>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec