spi: amd: Remove needless rom_addr variable

rom_addr is not used in the code, so we can just drop it from struct
amd_spi.

Signed-off-by: André Almeida <andrealmeid@collabora.com>
Link: https://lore.kernel.org/r/20220211143155.75513-3-andrealmeid@collabora.com


Signed-off-by: Mark Brown <broonie@kernel.org>