mtd: cfi_cmdset_0002: fix delayed error detection on HyperFlash

The commit 4844ef80 ("mtd: cfi_cmdset_0002: Add support for polling
status register") added checking for the status register error bits into
chip_good() to only return 1 if these bits are 0s.  Unfortunately, this
means that polling using chip_good() always reaches a timeout condition
when erase or program failure bits are set. Let's fully delegate the task
of determining the error conditions to cfi_check_err_status() and make
chip_good() only look for the Device Ready/Busy condition.

Fixes: 4844ef80 ("mtd: cfi_cmdset_0002: Add support for polling status register")
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>