Convert chips to block_erasers:
ST_M25PE10
ST_M25PE20
ST_M25PE40
ST_M25PE80
ST_M25PE16
PMC_25LV010
PMC_25LV016B
PMC_25LV020
PMC_25LV040
PMC_25LV080B
PMC_25LV512
PMC_39F010
PMC_49FL002
PMC_49FL004
SANYO_LE25FW203A
SPANSION_S25FL016A
Added spi_block_erase_d7 for PMC chips.
Signed-off-by: Sean Nelson <audiohacked(a)gmail.com>