Driver-API: Documentation: Replace deprecated :c:func: Usage

Replace :c:func: with func() as the previous usage is deprecated.

Signed-off-by: Puranjay Mohan <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Corbet <[e-mail]>

Documentation/driver-api/device-io.rst

···
 
 This address should not be used directly. Instead, to get an address
 suitable for passing to the accessor functions described below, you
-should call :c:func:`ioremap()`. An address suitable for accessing
+should call ioremap(). An address suitable for accessing
 the device will be returned to you.
 
 After you've finished using the device (say, in your module's exit
-routine), call :c:func:`iounmap()` in order to return the address
+routine), call iounmap() in order to return the address
 space to the kernel. Most architectures allocate new address space each
-time you call :c:func:`ioremap()`, and they can run out unless you
-call :c:func:`iounmap()`.
+time you call ioremap(), and they can run out unless you
+call iounmap().
 
 Accessing the device
 --------------------
···
 writeb(), writew(), writel() and writeq().
 
 Some devices (such as framebuffers) would like to use larger transfers than
-8 bytes at a time. For these devices, the :c:func:`memcpy_toio()`,
-:c:func:`memcpy_fromio()` and :c:func:`memset_io()` functions are
+8 bytes at a time. For these devices, the memcpy_toio(),
+memcpy_fromio() and memset_io() functions are
 provided. Do not use memset or memcpy on IO addresses; they are not
 guaranteed to copy data in order.
 
···
 
 Accesses to this space are provided through a set of functions which
 allow 8-bit, 16-bit and 32-bit accesses; also known as byte, word and
-long. These functions are :c:func:`inb()`, :c:func:`inw()`,
-:c:func:`inl()`, :c:func:`outb()`, :c:func:`outw()` and
-:c:func:`outl()`.
+long. These functions are inb(), inw(),
+inl(), outb(), outw() and
+outl().
 
 Some variants are provided for these functions. Some devices require
 that accesses to their ports are slowed down. This functionality is
 provided by appending a ``_p`` to the end of the function.
-There are also equivalents to memcpy. The :c:func:`ins()` and
-:c:func:`outs()` functions copy bytes, words or longs to the given
+There are also equivalents to memcpy. The ins() and
+outs() functions copy bytes, words or longs to the given
 port.
 
 Public Functions Provided