Reenable CONFIG_E1000_DELAY

[shruthi-ravi]

Commit https://github.com/ni/linux/commit/a555b1a73d6d17699a173983d5604613a55a6dbc added a delay after long writes on PREEMPT_RT-enabled kernels, but using the PREEMPT_RT_FULL option, which has since been replaced by just PREEMPT_RT. Therefore,

• update the delay condition to check on PREEMPT_RT instead.
• readd CONFIG_E1000_DELAY to nati_x86_64_defconfig

AzDO WI: 2114543

[gratian]

Rebased on top of latest nilrt/master/5.15 to account for PR https://github.com/ni/linux/pull/75, and submitted as commits:

• https://github.com/ni/linux/commit/3425c3b84bab9a085bf664fa13a64f129a01c778 ("nati_x86_64_defconfig: enable CONFIG_E1000_DELAY")
• https://github.com/ni/linux/commit/50ffc1c047f8323489c2072cb43886bf3eeae228 ("e1000e: Replace PREEMPT_RT_FULL with PREEMPT_RT")