zephyr: console: add missing include for shell_uart.h
zephyr: console: add missing include for shell_uart.h

Fixes few compiler warnings:

/mnt/host/source/src/platform/ec/zephyr/shim/src/console.c:40:13: warning: implicit declaration of function 'shell_backend_uart_get_ptr'; did you mean 'log_backend_count_get'? [-Wimplicit-function-declaration]
(and others)

BUG=none
BRANCH=none
TEST=zmake -lDEBUG configure... no warnings

Signed-off-by: Fabio Baltieri <1c55e39c05d9ab42261288cf330256b2af6ba179@google.com>
Change-Id: I1bb9b9a691559f93ea8530d530f00e5348e92cec
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2729047
Reviewed-by: Yuval Peress <50dc11c009bd4d7e9d9d15a383c1743ce5ee82ef@chromium.org>

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