sunxi:soc-detect: change sw_get_ic_ver() from const to pure

const functions don't have access to global mem, pure ones do.
sunxi:soc-detect: rename sunxi_chip_id() to sunxi_brom_chip_id()

because there are other methods

Signed-off-by: Alejandro Mery <amery@geeks.cl>
sunxi:soc-detect: export sunxi_brom_chip_id()

Signed-off-by: Alejandro Mery <amery@geeks.cl>
sunxi:soc-detect: add missing return to sunxi_pr_chip_id()
sunxi: introduce SUNXI_MACH_SUNnI defines using Allwinner's chipid values
sunxi:soc-detect: introduce sunxi_sramc_chip_id()

Thanks to hno's discovery

Signed-off-by: Alejandro Mery <amery@geeks.cl>
sunxi:soc-detect: add cached/pure sunxi_chip_id() and sunxi_is_sunNi() macros

Signed-off-by: Alejandro Mery <amery@geeks.cl>
sunxi:soc-detect: add extra debugging to sw_get_ic_ver() errors