Revert 'spi: spi-octeontx2: fix erase sector error by limit spi buswidth'

Revert commit e223229e

Commit e223229e

(spi: spi-octeontx2: fix erase sector error by limit
spi buswidth) try to fix erase sector error. After testing, spi-nor can
work normally without this commit now. It is not needed and causes follow
problem: 'spi spi0.0: setup: ignoring unsupported mode bits a00'

Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>