x86/boot: Drop redundant code setting the root device

[ Commit 7448e8e5 upstream ]

The root device defaults to 0,0 and is no longer configurable at build
time [0], so there is no need for the build tool to ever write to this
field.

[0] 079f85e6 ("x86, build: Do not set the root_dev field in bzImage")

This change has no impact on the resulting bzImage binary.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230912090051.4014114-23-ardb@google.com


Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>