[PATCH] docs: replace `-hda` with `-drive` & update `root=` kernel parameter

[Integral via <qemu-devel@nongnu.org>]

According to QEMU manual:

Older options like `-hda` are essentially macros which expand into
`-drive` options for various drive interfaces. The original forms
bake in a lot of assumptions from the days when QEMU was emulating a
legacy PC, they are not recommended for modern configurations.

Signed-off-by: Integral <integral@archlinuxcn.org>
---
 docs/system/gdb.rst         | 2 +-
 docs/system/linuxboot.rst   | 6 +++---
 docs/system/target-mips.rst | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/docs/system/gdb.rst b/docs/system/gdb.rst
index 4228cb56bb..d50470b135 100644
--- a/docs/system/gdb.rst
+++ b/docs/system/gdb.rst
@@ -20,7 +20,7 @@ connection, use the ``-gdb dev`` option instead of ``-s``. See
 
 .. parsed-literal::
 
-   |qemu_system| -s -S -kernel bzImage -hda rootdisk.img -append "root=/dev/hda"
+   |qemu_system| -s -S -kernel bzImage -drive file=rootdisk.img,format=raw -append "root=/dev/sda"
 
 QEMU will launch but will silently wait for gdb to connect.
 
diff --git a/docs/system/linuxboot.rst b/docs/system/linuxboot.rst
index 5db2e560dc..2328b4a73d 100644
--- a/docs/system/linuxboot.rst
+++ b/docs/system/linuxboot.rst
@@ -11,7 +11,7 @@ The syntax is:
 
 .. parsed-literal::
 
-   |qemu_system| -kernel bzImage -hda rootdisk.img -append "root=/dev/hda"
+   |qemu_system| -kernel bzImage -drive file=rootdisk.img,format=raw -append "root=/dev/sda"
 
 Use ``-kernel`` to provide the Linux kernel image and ``-append`` to
 give the kernel command line arguments. The ``-initrd`` option can be
@@ -23,8 +23,8 @@ virtual serial port and the QEMU monitor to the console with the
 
 .. parsed-literal::
 
-   |qemu_system| -kernel bzImage -hda rootdisk.img \
-                    -append "root=/dev/hda console=ttyS0" -nographic
+   |qemu_system| -kernel bzImage -drive file=rootdisk.img,format=raw \
+                    -append "root=/dev/sda console=ttyS0" -nographic
 
 Use Ctrl-a c to switch between the serial console and the monitor (see
 :ref:`GUI_keys`).
diff --git a/docs/system/target-mips.rst b/docs/system/target-mips.rst
index 83239fb9df..9028c3b304 100644
--- a/docs/system/target-mips.rst
+++ b/docs/system/target-mips.rst
@@ -112,5 +112,5 @@ https://mipsdistros.mips.com/LinuxDistro/nanomips/kernels/v4.15.18-432-gb2eb9a8b
 Start system emulation of Malta board with nanoMIPS I7200 CPU::
 
    qemu-system-mipsel -cpu I7200 -kernel <kernel_image_file> \
-       -M malta -serial stdio -m <memory_size> -hda <disk_image_file> \
+       -M malta -serial stdio -m <memory_size> -drive file=<disk_image_file>,format=raw \
        -append "mem=256m@0x0 rw console=ttyS0 vga=cirrus vesa=0x111 root=/dev/sda"
-- 
2.49.0