doc(chip): Revise testplan to cover any sleep modes.
doc(chip): Revise testplan to cover any sleep modes.

To cover `chip_sw_random_sleep_pin_wake` test, the
`chip_sw_sleep_pin_wake` covers normal sleep mode too. This commit
revises the testplan to mention the deep/ normal sleep states.

Signed-off-by: Eli Kim <3ca62a2ad87376be2697209a1770e1afdbbba220@opentitan.org>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan