Enabling the kernel boot parameter 'hpet_mmap' does not take effect.

Issue

• The kernel parameter hpet_mmap is used to enabled/disable (default) HPET MMAP. However, booting the kernel with this parameter does not take effect and always takes the default value (0) of hpet_mmap_enabled.

• dmesg output after booting the kernel with the kernel parameter hpet_mmap=1

# cat /proc/cmdline 
BOOT_IMAGE=(hd0,msdos1)/vmlinuz-4.18.0-32.el8.x86_64 root=/dev/mapper/rhel-root ro crashkernel=auto resume=/dev/mapper/rhel-swap rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap hpet_mmap=1

# dmesg | grep 'HPET mmap'
[    0.000000] HPET mmap disabled

• dmesg output after booting the kernel with the kernel parameter hpet_mmap=0

# cat /proc/cmdline 
BOOT_IMAGE=(hd0,msdos1)/vmlinuz-4.18.0-32.el8.x86_64 root=/dev/mapper/rhel-root ro crashkernel=auto resume=/dev/mapper/rhel-swap rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap hpet_mmap=0

# dmesg | grep 'HPET mmap'
[    0.000000] HPET mmap disabled