hpet: Fix missing '=' character in the __setup() code of hpet_mmap_enable

BugLink: https://bugs.launchpad.net/bugs/1828420

[ Upstream commit 24d48a61 ]

Commit '3d035f58 ("drivers/char/hpet.c: allow user controlled mmap for
user processes")' introduced a new kernel command line parameter hpet_mmap,
that is required to expose the memory map of the HPET registers to
user-space. Unfortunately the kernel command line parameter 'hpet_mmap' is
broken and never takes effect due to missing '=' character in the __setup()
code of hpet_mmap_enable.

Before this patch:

dmesg output with the kernel command line parameter hpet_mmap=1

[    0.204152] HPET mmap disabled

dmesg output with the kernel command line parameter hpet_mmap=0

[    0.204192] HPET mmap disabled

After this patch:

dmesg output with the kernel command line parameter hpet_mmap=1

[    0.203945] HPET mmap enabled

dmesg output with the kernel command line parameter hpet_mmap=0

[    0.204652] HPET mmap disabled

Fixes: 3d035f58 ("drivers/char/hpet.c: allow user controlled mmap for user processes")
Signed-off-by: Buland Singh <bsingh@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

drivers/char/hpet.c

@@ -376,7 +376,7 @@ static __init int hpet_mmap_enable(char *str)
 	pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled");
 	return 1;
 }
-__setup("hpet_mmap", hpet_mmap_enable);
+__setup("hpet_mmap=", hpet_mmap_enable);
 
 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 {