package, toolchain: remove BR2_TOOLCHAIN_HAS_GCC_BUG_* options

Quite some time ago, we added the options
BR2_TOOLCHAIN_HAS_GCC_BUG_58595 and BR2_TOOLCHAIN_HAS_GCC_BUG_58854 to
indicate if the toolchain was affected by those gcc bugs, which were
causing build failure with a number of packages.

With the recent change in the external toolchain logic to provide only
the latest version of each toolchain "family", all the toolchains
which were affected by those issues disappeared from Buildroot. Those
options are no longer being selected anywhere, and being blind
options, it means their value is always going to be "disabled".

Conquently, this commit removes those options completely, and updates
all the packages where they were used.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>