pm: npcx: consider host wake-up features only if espi is selected.

This CL limits the compiler to consider the eSPI/LPC host wake-up
functions, such as npcx_host_disable_access_interrupt and
npcx_host_disable_access_interrupt, only if eSPI bus module is selected.
Otherwise, we will encounter compiler errors if the communication
between host and ec is via SPI, not eSPI/LPC bus.

Signed-off-by: Mulin Chao <mlchao@nuvoton.com>